Information

What are the features on a microscope one needs in order to do lab work?

What are the features on a microscope one needs in order to do lab work?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

By lab work I mean urinalysis, blood work(live as well), fecals, cytologies, histologies and all other.

I have read(partly) a book(from 2002) on lab diagnostics and the author did not mention anything about diagnostics. I've spent a lot of time searching on google as well and I did not get anything.


It sounds like you need a microscope for standard microbiology lab tests. At a minimum, any standard wide-field/brightfield microscope would work. If most of your histology work involves colorimetric stains (e.g., H&E, gram staining), you don't need any fluorescence capability. If you are working with a lower budget, look at the new lines of LED-based miroscopes, which dramatically drop the cost (I think around $10,000).

If you plan on doing a high volume, in particular of fixed histology/cytology slides, then you may want to invest in some of the automated slide scanner microscopes. They have a small benchtop footprint and can be programmed to image large areas automatically, for later analysis.


Microscope Cell Lab: Cheek, Onion, Zebrina

The purpose of this lab was to use the microscope and identify cells such as animal cells and plant cells. This subject is important because in Biology, we will be using the microscope many times during different laboratory exercises. The microscope is used for looking at many specimens that cannot be seen with the naked eye.

Humans only have a resolution, the ability to separate or distinguish two or more objects that are close together, of 0.1 millimeters. The average microscope has a resolving power of up to 0.2 micrometers. In this lab, we adjusted the resolution on the microscope to have a better look at the specimens that were observed. In addition, we needed to look at the contrasts of some specimens in this lab.

Contrast is defined as being able to see different parts of the specimen at hand. In this lab, in order to increase the contrast of some specimens, we stained the samples using Methylene Blue and Water. The main hypothesis of this lab was, can we use the compound microscope to look at samples that we normally cannot see with our unaided eyes?

Materials, Methods, and Results

In this laboratory exercise, our main instrument was the compound microscope. In order to prepare the samples for observation certain materials were used. I used tools such as:

  • Compound Microscope
  • Toothpicks
  • Slides
  • Cover slips
  • Methylene Blue
  • Water
  • Onion bulb
  • Forceps
  • Razor blades
  • Onion bulb
  • Zebrina stem
  • Laboratory Exercise Manual
  • Pencil

There were three mini-lab procedures carried out during this lab. The first lab exercise was observing animal cells, in this case, my cheek cells.

The second lab exercise was observing plant cells, in this case, onion epidermis.

The third lab exercise was observing chloroplasts and biological crystals, in this case, a thin section from the Zebrina plant.

The first thing that was done in this lab exercise was gather materials. I worked with two other classmates that sat at my table.

Observation of animal cells (squamous epithelium of a cheek)

Using a toothpick, I carefully scraped the inside of my cheek to get the cells. I then spread it across the slide, added the Methylene Blue solution, and then covered the slide with a coverslip. I placed the slide in the center of the stage and made sure it was secured with the stage clip.

The objective lens was already at 10X magnification, so I switched it to 40X magnification. I moved the stage closer up using the Coarse Adjustment. The specimen wasn’t exactly in the middle, so I had to move the slide around using the X-Y stage control so that I was looking directly at the sample.

I also adjusted the lighting of the microscope using the diaphragm. I then switched the magnification to 40X. I adjusted the Fine Adjustment to get a sharper image of the cell. I was able to see the cheek cell correctly. I was able to see the Cytoplasm, Nucleus, and Cell Membrane.

Observation of plant cells (onion epidermis)

For this observation, a plant cell was to be seen. An onion bulb was retrieved. Using the forceps, I removed a small slice of the onion and carefully and quickly put it on the slide. I also added water to ensure that the onion slice would not dry out.

I adjusted the lighting again using the diaphragm, to contrast the compartments of the cell. I moved the stage closer up using the Coarse Adjustment and switched the magnification to 10X. I was able to see the Nuclei and Cell Walls between each cell.

Observation of chloroplast and biological crystals

For this observation, I looked at a small section from the Zebrina stem. The stem was gotten from the bucket in front of the classroom.

The small section was obtained by slicing a tiny amount of the stem using the razor blade. It was placed on the slide, followed by the water. When first observed, nothing clear could be seen.

It appeared to be that the Zebrina stem was cut too thick. The stem had to be cut once more, and this time much thinner, but not too thin. The same procedure was repeated again, adding water, placing the coverslip, putting the slide on the stage, adjusting the stage, and making the image sharper.

The second sample proved to be much better. The magnification was already positioned at 10X magnification, which made the cell much clearer to see. The Cell Walls, Cytoplasm, Nucleus, Chloroplasts, and Crystals were able to be seen.

To find the resolving power for each of the lenses on the compound microscope, I used the Abbey equation. I plugged in the appropriate numbers into the variables, where d = resolution (nm), 0.612 was given, l = wavelength of light used (550 nm), and NA = numerical aperture. I repeated this equation for each magnification, getting the resolving power for each of the lenses.

  • Will this resolution be attained with each sample you look at? What will be some of the interfering factors?

Each resolution for each sample is different. Some samples will require you to choose a higher magnification or lower magnification. Some interfering factors can be using contaminated samples such as dirty slides, using the wrong stains or dyes, using the incorrect sample, broken slides, and many more.

Other interfering factors could be for using incorrectly using the equipment or broken equipment such as broken objective lens, broken illuminators, the light might be too high or too dim, and many more.

When the Numerical Aperture increases, the resolving power will decrease.

  • What differences can you observe between animal cells (cheek epithelium) and plant cells (onion epidermis)? Think of the size, shape, and cellular components.

The onion epidermis cell is the only cell that has a cell wall. In addition, it is the only cell that has a chloroplast, where photosynthesis can happen. The cheek epithelium cell is the only one that has centrioles, the barrel-shaped organelle that is responsible for helping organize chromosomes during cell division.

Furthermore, the presentation of the onion cells was positioned right next to each other, on top of each other, below each other, like a checkerboard. The cheek cells were bunched up together at some areas, almost overlapping each other. The onion cells almost looked rectangular-shaped, whereas the cheek cells look oval-shaped.

From looking at the Zebrina slide, I would estimate that there was about 50 chloroplasts.

Calcium oxalate is a calcium salt of oxalic acid. It forms crystals known as raphides, which appears to be what I saw when l looked at the Zebrina sample. Interestingly enough, while reading about calcium oxalate, I discovered that it is a major constituent of human kidney stones, founded in the urine.

From observing the calcium oxalate crystals, it looks like spikes/needles. From what I know about spikes, they serve as a weapon. So my assumption is that these crystals are used as a defense of some sort.

Help Us Fix his Smile with Your Old Essays, It Takes Seconds!

-We are looking for previous essays, labs and assignments that you aced!

Related Posts

Complement Protein: special proteins that expand/puncture the pores in membranes on foreign microbes allowing extracellular&hellip

A cell is the basic unit of life, and all organisms on earth are made&hellip

Nucleus: Contains most of the genetic info in the eukaryotic cell (some genes are located&hellip

Introduction This lab will answer whether or not initial speed affects the time that a&hellip

Introduction Every somatic cell undergoes a phase called mitosis. Mitosis is the division of the&hellip

Author: William Anderson (Schoolworkhelper Editorial Team)

Tutor and Freelance Writer. Science Teacher and Lover of Essays. Article last reviewed: 2020 | St. Rosemary Institution © 2010-2021 | Creative Commons 4.0


My First Lab Microscope - The Duo-Scope

Looking for the best kids microscope? The Duo-Scope My First Lab Microscope by C&A Scientific is a great tool and toy for the budding scientist (even if that "budding scientist" is a 32 year old reviewer). We've tested many microscopes for little ones over the past few years, and this is one that keeps coming out on top.

Choosing a microscope for your child isn't always so cut and dry. You want a product that's simple to use, fun, and educational without spending like you're outfitting a college science lab. With all the options out there vying for a parent's attention, it's easy to end up with an empty wallet and a frustrated child.

That's why we feel for features versus cost, the versatility and function of the Duo-Scope makes it one of the best beginner microscopes on the market. It may not come with as much in-depth microscopy information as the TK2 Scope, but it's fun, easy to use, and allows kids to develop their science skills and an interest in the microscopic world.

One of the biggest selling points of the My First Lab microscope is that it functions as both a compound biological and stereo dissecting microscope. This means that you can look at either microscopic specimens on a flat slide or solid 3D objects like bugs and coins (more on this later). This powerful feature makes it essentially two microscopes in one.

Throw in tons of useful accessories and it's easy to see why it was named Creative Child Magazine's "Top Toy" a few years ago. With all the products out there, this was one of the best microscopes we found to satisfy the ravenous curiosity of a young scientist.

So let's rip this baby open and show you what it looks like! If you're short on time, skip to the summary and recommendations section below.

My First Lab Microscope Duo-Scope Review

Packaging and Setup:

I was excited to get the light, easy to carry box that contained the Duo Scope. The box itself is bright yellow and fun, describing the various ways you can use the microscope. I was a little disappointed to see a typo right off the bat, but it certainly wasn't enough to ruin the first impression.

The My First Lab microscope itself comes neatly wrapped in a plastic bag and sits well protected in another egg carton style box. Most of it is already put together, and the package also contains the eyepiece, a manual, and a smaller box holding the accessories.

Assembly was painfully easy, something any parent can appreciate. Just screw in the separate eyepiece and you're ready to go!

You'll also need 3 AAA batteries, which aren't included. At least they tell you that straight away on the box. After you steal them from the TV remote (isn't that where all batteries come from?), they go in the bottom compartment.

Below is the My First Lab microscope all set up with the parts labeled.

My First Lab Microscope Construction and Specifications:

Nobody likes a cheaply made product, especially when that product is going to have to withstand the rigors of a childlike mind and curious little hands!

After a thorough examination, I have to say that this kids microscope seems very sturdy. Yes, the main body is made up of a lot of plastic, but it's by no means flimsy. The construction is solid and should definitely stand up to an average level of kid curiosity.

Of course I wouldn't toss it around, drop it from the second floor, or treat it like a football but with a little care it should last a long time. I can attest to the strength of the eyepiece, as much to my horror it jumped out of my hands (all on its own!) and fell at least 4 feet onto a wooden table. It still worked fine after that. (Phew!)

  • 10X Eyepiece (Quite sturdy, as I discovered the hard way)
  • 4X, 10X, 40X Objectives (These are the rotating lenses at the top of the head. Multiply the lens number by the 10X power of the eyepiece and you get the true magnification. So using the 4X objective gives you a 40X magnification.)
  • Dual focusing knobs (Perfect for both right or left handed kids)
  • Rotatable head (I didn't need to move the head but you can if you need to)
  • Real glass optics (Which yielded very nice images)
  • Disc diaphragm with 6 holes (For allowing more light to shine on slides)
  • LED light sources (For upper and lower illumination of the specimen)
  • Battery operated (So you can bring it outside)
  • Accessory kit (More on that later)
  • Manual

Many people don't know what a disc diaphragm is. Also called an iris diaphragm, it's simply a rotating disc that sits under the stage. Located between the slide and the light source, it has different sized holes so you can change the amount of light shining up through the specimen.

The smaller holes are for the lower magnifications, while the larger holes are for the larger 400X magnification. That said, there's no hard and fast rule for using a disc diaphragm. Whether you need to rotate it depends on the level of contrast you want and how translucent the specimen is. It's easy to find and move around so it's just a matter of experimentation.

As for the rest of the My First Lab microscope, the dimensions listed in the manual are 4.5" x 6.5" x 11.5" high. I was surprised at the 1.95 pound net weight. For the sturdy construction it is quite light.

The whole kit is very well built. There are no disturbing sounds of rattling pieces, the mechanisms work smoothly, and the objectives click soundly into place when changing the magnification.

Using the My First Lab Microscope:

A quick breeze through the manual was all I needed to get started using the Duo Scope. In moments I was looking at a prepared slide that came with the kit, and then combed the house for any spider web, dust bunny, or creepy crawlie that I could view. The optics and image quality were great, providing clear crisp images that weren't blurry.

The big selling point of this kids microscope is that it's two scopes in one, hence the Duo Scope title. It's both a compound biological microscope (meaning you can use it to view flat slides), and a dissecting stereo microscope (meaning you can use it to view 3D objects). Switching between the two modes is merely a matter of flipping the switch on the back.

When used as a compound microscope, a light comes from below to illuminate the slide. Simply place the slide on the stage (the main viewing platform), secure it with clips, and make sure the specimen is centered directly over the hole in the stage where the light shines through.

The Duo Scope offers 3 magnification settings in this mode: 40x, 100x, and 400x. You can switch between them by rotating the objective lenses (the 3 lenses sticking out of the head on the top). I tried this out myself by looking at one of the prepared slides that came with the kit. I chose the mouth smear, which in addition to being an awesome name for a band turned out to be incredibly fascinating to view.

At 40x I could see the cells, jagged yet geometric. You have to adjust the focusing knob on the side every time you change objective lenses, as the slide needs to be closer to the lens to see at the larger magnifications. Looking at the slide at 400x was pretty mind blowing, and my initial delighted disgust at viewing some cells on the inside of a stranger's mouth fizzled into pure fascination.

It's worth noting that the 400x magnification option could pose a potential problem for overzealous young ones. In order to see anything, the slide has to be so close to the lens that they're almost touching. If you turn the focus knob too much or too quickly you could break the slide or damage the lens.

Switching between the magnification settings was easy and intuitive. Definitely not too complicated for a child, but I'd recommend a quick explanation and demonstration of the 400x setting so s/he knows to be a little more cautious when using the highest magnification.

Next I flipped the switch on the back to turn it into a stereo microscope. With this option, the light comes from above to illuminate a 3 dimensional specimen such as a rock, insect, coin, etc. There's no point in having light come from below, as it won't penetrate a solid object.

Using the stereo option is even easier, and possibly even more fun. Place the object on the stage (I used a penny in the picture below), and make sure it doesn't fall through the hole. You may want to put it on a piece of white paper for easier viewing.

The My First Lab microscope offers 2 magnification settings here: 40x and 100x. The 400x option won't work, as light won't reach the specimen due to the extremely short focusing distance needed. This is common with stereo microscopes, which operate at lower magnifications.

Don't be disappointed though. The two magnifications offered are outright awesome. I first looked at a penny, which was pretty cool. I then pinched off a budding little flower of a fuzzy houseplant and was very impressed by the amazing level of detail I could see, like looking at a jungle.

Keep in mind that when viewing a 3D object there are different levels to focus on. Since it's not flat, the entire image isn't clear all at once. So you'll have to use the focusing knob to see the various levels of an object. This turned out to be a lot of fun, like zipping around your specimen up close in a tiny ship!

Overall I was very impressed with the functioning of the My First Lab microscope. It was easy to use, fun to play with, and the images were outstanding. Given how tech savvy kids are now, they should pick it up in no time. A quick demonstration and a few cautions by Mom or Dad should be all they need to get started.

Included Materials:

The My First Lab microscope comes with some fun accessories, although not over 50 as they advertise on the box. The included accessories are:

  • 5 blank slides
  • 4 prepared slides
  • A concave blank slide
  • Cover glass
  • Plastic dropper
  • Two bottles of stain (non-toxic food coloring)
  • Slide labels
  • Lens paper
  • Forceps
  • Test tube
  • Petri dish
  • Teasing needle

Although not exhaustive, this is a great collection of accessories. The options these accessories open up really lets a kid delve deeper into microscope use and allows for hours of scientific "play".

For the prepared slides, our kit came with pollen, mouth smear, paramecium, and salt crystals. I'm not sure if those come with every kit or if they have a few more that they rotate, but I enjoyed them all (especially the mouth smear and the salt crystals). These prepared slides let a kid start using the microscope right away without having to do anything else. This instant gratification will keep them interested in the beginning, when attention spans sometimes waver.

To further that interest, the kit comes with everything you need to make your own simple slides. You can put any sort of crystals, hair, or pollen on the blank slides, or try a drop of pond water on the concavity slide.

Many of the accessories are useful with 3D objects too, such as using the teasing needle or tweezers to move around an insect. You could also put a small piece of bread or food in the Petri dish, which should be revoltingly enthralling after a few weeks for kids and adults alike!

Some of these objects are glass or are a little sharp so I would recommend adult supervision for the younger set. Overall the accessories are easy to use and relatively harmless.

This kids microscope also comes with a helpful manual that contains instructions, lists, and some observation ideas. It gives directions on how to make your own slides, and how to best maintain the My First Lab microscope. The manual itself is short (about 10 pages), but has everything you need to know in it. It's informative, easy to read, and makes sense.

My First Lab Microscope Customer Service:

As Microscope Detective purchased this item directly for me to try and wasn't given it for free, we didn't really have any contact with the maker C&A Scientific. However, a little research revealed that this company has been around for a while and makes many different types of highly rated microscopes.

The manual also says it comes with a limited one year warranty. If you have a problem resulting from a manufacturing defect under normal use, they'll repair or replace it for you for free. Of course that doesn't cover damages incurred from accidentally stepping on it in the middle of the night, but they do say they'll fix a legitimate defect for free (you pay shipping).

Judging by their many successful products and my personal experience with the Duo Scope, C&A Scientific seems on the level and I would purchase something from them again.

Pros and Cons of the My First Lab Microscope

  • Good quality glass optics
  • Two microscopes in one: both compound and stereo
  • Easy to use
  • Sturdy construction
  • Useful accessories
  • Helpful manual
  • Usually retails for between $60 and $70, a great price for all the features
  • Carrying case or dust cover not included (they do advise you to use the plastic bag it comes in as a dust cover, but it would be nice to have a real one).
  • Upper and lower lights can't be turned on at the same time, which may make it difficult to view translucent specimens that need lots of light.
  • The box says over 50 accessories, but I count only around 20. Is this advertising hyperbole or am I just missing something?

My First Lab Microscope Summary

The My First Lab Microscope is a great product in a very reasonable price range. It is designed to nurture a love of science in kids, and made to last and grow with the user. If you're into science, this could entertain anyone for days. I had a blast using it.

The downsides seemed small when compared to the advantages. It's way under $100, easy to use, comes with lots of accessories, and provides a really nice image. What more could a parent want?

Ultimately, it's just a lot of fun. After I used it I left it set up for my better half to play with, which lasted far longer than I thought it would. This is the kind of item that can really change how you see life, take you from ignorance to knowledge, and engender a deep fascination for the world around you.

The My First Lab Microscope Is Recommended For:

A better statement would be for whom it isn't recommended. It's not powerful enough for a serious scientist or graduate student, but should be perfect for anyone else looking for a simple and fun compound microscope, stereo microscope, or both!

The box says that it's for kids in the eight and up age bracket, but I feel my 7 year old nephew could use and enjoy it. The kit includes both delicate and sharp instruments, so if you buy it for a younger scientist you may want to supervise and edit the kit as needed.

Of course, if you're a curious adult this could be a great purchase too! Although it is a kids microscope, I wouldn't classify it as a simple "toy". Adults needing to look at slides up to 400X can get a lot of use out of it, as could entomologists, jewelers, stamp collectors, or anyone wanting to view 3D objects for work or fun.

If you're looking for something a little more comprehensive with more experiments included take a look at the TK2 Scope. It's a complete biology kit that offers a little more for teachers, home schooling parents, or kids who really love biology. Yet if you're looking for a versatile and fun beginner kids microscope, the Duo Scope is the one.

Now if you'll excuse me, I have to go find something else cool to look at. I'm sure there's a dead bug around here somewhere!

Rating (4.5 out of 5):

The My First Lab microscope was our top pick for kids, but we also gave high marks to the TK2 Scope and the Konus Konuscience Zoom 1200x Biological Microscope.


Cell Types Detective Activity

Biologist's Report on Unicellular Infections in the New York Aquarium

In this Problem Based Learning activity students will identify different types of cells to help the New York aquarium re-open. Aquarium tanks flooded during the storm surge from hurricane Sandy must be clear from infections before being restocked. They will write a report to explain their findings and outline the features of each cell which enabled it to be identified as, eukaryotic plant cells, animal cells or prokaryote cells.

Guiding Questions

Which cell structures are most useful when identifying different cell types?

What are the organelles in prokaryote cells, and eukaryote cells?

The New York Aquarium in Brooklyn was closed after being inundated by the storm surge from Hurricane Sandy last autumn. The storm surge jumped the Coney Island Boardwalk on the evening of Oct. 29 2012, pouring sea water into the five buildings on the 14-acre complex. The floodwaters cascaded down the stairs of the buildings, filling up baseme nts with 10 to 15 feet of water, and flooded the ground floors with two to three feet. See more images and a news report about hurricane sandy at the NY aquarium

For days, aquarium officials thought they would need to evacuate the entire collection of 12,000 fish and marine mammals to other aquariums on the East Coast. Staff members were able to stave off an evacuation by working around the clock to pump water out of basements and get emergency generators running. Since then the animals have been in special quarantine tanks.

Before the aquarium can re-open the the aquarium vet must be sure that there are no diseases in any of the tanks. Diseases can be caused by single celled protoctista (made from eukaryotic animal cells) or bacterial infections (made from prokaryotic cells). Algae do not normally harm the fish (they are made from eukaryotic plant cells)

Activity 1 - Expert Biologist's Report

You are a cell biology specialist. Samples taken from water in each of the five aquarium tanks have been loaded into the New York aquarium's electron microscope, below. Electron Microscope Slide Viewer - ppt file

Your job is to analyse these images.

Identify which type of cells they are eukaryote animal cell, eukaryote plant cell or prokaryote.

For each slide, explain how you have identified the cells and complete the Student Worksheet - a template for the Expert Biologist's Report

Extension idea:

For students interested in keeping fish as a hobby or a career in marine Biology this link is worth reading:
Common aquarium fish diseases (Algone) (Thanks Amit K for this suggestion.)

Activity 2 - Revision of Cell Types and their Organelles

If you need to review the structure of eukaryote and prokaryote cells and revise cell organelles, use this excellent online tutorial, and online quiz. http://www.sheppardsoftware.com/health/anatomy/cell/index.htm

Activity 3 - IB Style Questions on Cell Types

To test your knowledge of cells and their organelles answer these IB style questions

Teachers notes

This activity is a good summary of the work on cells. It tests the students skills at interpreting electron microscope images and leads well to work comparing prokaryote and eukaryote cells or the comparisons between plant and animal cells.

All three activities, including the IB style questions could be completed by a good students in 1 hour.

Some students may prefer to begin with activity 2 but more confident students should try activity 1 first and use the second activity to help resolve any uncertainties.

The electron microscope activity could be extended to include calculating the sizes of various cell components, although the students will discover that the magnifications of the slides are approximate.


Digital Microscope Camera Guide and Features

Since there are so many microscope cameras to pick from, you will need important information for a complete digital microscope camera. When you buy a digital microscope camera there are a variety of factors you need to look for to guarantee you are buying the best camera. Here is a list of features to look for in digital microscope cameras below:

Resolution:

Compatibility:

Data Transfer Speed:

Software Integration:

Versatility:

CCD vs. CMOS:


What are the features on a microscope one needs in order to do lab work? - Biology

Unread post by DS4home » Tue Jul 08, 2008 1:38 pm

Yes, you do need the extras. If you want to be able to give a full high school credit for Biology the student needs to do the lab portion of the curriculum along with reading the textbook. I bought our microscope and dissection kit from Home Science Tools ( I think). It's been a couple years.

Unread post by Lucy » Tue Jul 08, 2008 2:37 pm

MFW gives you a couple of places that you can order these from in the lesson plan book that comes with the package. One is the Apologia site https://apologia.securesites.net/store/ . Path=26_29 and the other is http://www.naturesworkshopplus.com .

As Dawn has already said you will need these item. I have to order this soon too for my daughter!

Unread post by gressman9 » Wed Jul 09, 2008 1:07 am

You might want to check with Knight's Book Nook, too. Though I don't know if they have a website or if you just call them. They are located in GA, but travel to a lot of homeschool conferences. They sell all the kits, microscopes and other science related stuff. Like MFW . they are a homeschool family business.

Apologia Science Biology Question

Unread post by KimberlyND » Sun Aug 30, 2009 9:48 am

We did purchase a microscope when our oldest was doing biology. The homeschool company that sold it was Nature Workshop Plus. I went to their site. The microscopes are a little more expensive than when we bought ours. And they have a lot more to choose from. We have always been very happy with the one we got.

I know others have found used microscopes they bought from public schools. I guess you would have to determine what type you needed. If you called the MFW office I'll bet they could help you with that and the original question of whether you need one.

I have never been sorry that we got our microscope. I don't know if it is necessary to have one to do the text as now you can get the "Multimedia Companion CD for Exploring Creation with Biology." Pray about it as it is a big money investment, check on what type you would need, and look around for the best prices if you decide you will get one.

Re: Apologia Science Biology Question

Unread post by Julie in MN » Sun Aug 30, 2009 10:14 am

I remember agonizing over this with my older dd. Like Kimberly, I personally think you could manage without one but might confirm with the MFW office (it should be in your MFW Lesson Plans but I see you don't have those yet). Lucy & Dawn both seem to find it important here: [above]

I bought ours at Sonlight & I felt it was competitively priced. There are even more features you can get at places like HomeScienceTools, such as stereo view (like eyeglasses with two lenses) or dual view (where mom & son can both look at same time), but ours is fine.

We take it out every year for one thing or another, and I'm happy to be able to provide that experience to my children. I will say that I learned (a) not to get a toy -- I actually visited a local laboratory store to ask/see what the difference was & it's no competition and (b) not to expect it to be totally easy to work with, since these tools take some amount of focusing & manipulating, depending on the specimen.

Re: Apologia Science Biology Question

Unread post by cbollin » Sun Aug 30, 2009 2:01 pm

Basically, there are 3 kinds of lab experiments in Apologia Biology. In order to receive high school biology with lab credit, Apologia on their website recommends that you do all of at least 2 types of experiments:
1. standard labs that were "household" items (all students should do these)
2. labs with microscope and slide set. these are optional
3. dissections -those require the dissection kits. optional, unless you are taking the internet version of the class.

So, for lab credit, you have to do the "household items" one. and then choose either the microscope and slides, or dissections. So if you can't afford a microscope you can skip it and just get the dissection kit. Apologia says it has worked with nature workshop Plus! to get good quality, lower cost for a microscope if you can afford it.

in any case. just in case there are other places that a microscope is useful outside of the lab credit, try to find someone near you to share it with. I know when I was in Indiana, there was always someone ahead of me in Apologia. They said "hey if you need to share a microscope. " Maybe you can find someone to cost share.

Microscope Selection Help! PLEASE

Unread post by DS4home » Wed Nov 11, 2009 4:12 pm

amelasky wrote: I have an urgent request. Will those of you with "older" children, please let me know what microscopes that you use. If you like them, and why OR if you don't like them and why.

My parents are requesting that I give them the information on which microscope that is a good one, and they want to BUY one for us for Christmas. I do not know where to even begin! Terrible coming from a certified Science teacher, I know.

There are digital ones, and battery powered, and SO many choices. We don't want a "toy" one, but one that will last us through High School. Thank you SO much for your help!

We bought the one Apologia recommends, when my oldest did Biology. I had no idea what to look for, so I went with their recommendation. It has been fun to use. It is a very durable, high school level, microscope. You won't go wrong with this purchase, IMO. We also got the premade slides - they were really cool

Re: Microscope Selection Help! PLEASE

Unread post by KimberlyND » Wed Nov 11, 2009 4:51 pm

Re: Microscope Selection Help! PLEASE

Unread post by Julie in MN » Wed Nov 11, 2009 6:33 pm

Hi Annie,
What a great thing for your parents to do!

    When I started homeschooling, I had a high schooler & spent a lot of time researching microscopes. I even bought a few "mistakes" off of eBay or somewhere.

I finally found a local microscope store & went there in person to see what I was looking for. They were not really designed for shoppers like me, but were very kind. They explained all the features that I had read about online, and let me see the difference in person. (They were very forgiving that I could not afford their materials & bought from Sonlight -- though I think I got some little thing from them.)

Now-a-days, you can look at microscopes at some conventions. What a great opportunity!

The two things I think I learned through my experience were (1) real microscopes are in a different price range than toys, and (2) the amount of magnification is not really the issue because some impressive higher powers are only useful for looking at parts of cells or something your kid is unlikely to ever need.

One thing we don't have is "binocular" type viewers for two eyes (stereo). I think that might be nice but we've done fine without it. Also, there are a couple popular durable low-power microscopes which would be fun for viewing rocks & bigger things, but we've had to settle for a magnifying glass

Chemistry

Unread post by cbollin » Mon Jan 11, 2010 6:37 am

I've glanced at the lab list by each module on their site, nice to see what comes in the kit that way.

I wondered the same thing too -- especially about that choice 2 lab kit
I'm looking forward to hearing those who have done chemistry.

Re: Chemistry for 10th grade

Unread post by LA in Baltimore » Mon Jan 11, 2010 10:00 am

Supply kit/microscope for Apologia Biology?

Unread post by cbollin » Sun May 02, 2010 6:19 pm

I just bought my microscope for Apologia Biology from Home Science Tools. They sell kits for Apologia.

That company recommends this one for high school stuff and it seems good enough to us
the model is Item# MI-4100STD
and that site is hometrainingtools.com
(even though they aren't a direct competitor, I think I'll just say the web site instead of linking. )

cost is about $180.
and we got the slide kit from them too.
I was very pleased with their service and shipping. fast. Not costly shipping (which surprised me). So far, we're happy with it from playing with it.

MFW's lesson plans recommend Nature's Plus Workshop -- but that price is higher. But NWP is the pseudo official supplier that Apologia recommends. They sell the stuff that shows up on the same recommendations as Apologia's website.

oh. there's a note in the MFW plans -- if you order the dissection stuff -- plan to not get it too early in the year. Order later because specimens for dissection have limits on that stuff.

But yeah, for a high school lab quality microscope,--- you should be expecting about $200 ish range. I know. I fainted too. But as my dh said "better than the $20,000 equipment we have in the lab".

Re: Supply kit/microscope for Apologia Biology?

Unread post by Tracey in ME » Sun May 23, 2010 7:00 pm

- Tracey
Mother of six (16, 13, 9, 7, 4, and 15 months)
2006 - Present - My Father's World
2001-2005 Sonlight

Re: Chemistry for 10th grade

Unread post by Bret Welshymer » Sun Jun 13, 2010 7:25 pm

Re: Chemistry for 10th grade

Unread post by Teresa in TX » Sun Jun 13, 2010 7:35 pm

Teresa, Mom of 5: 15yo dd, 12yo ds, 7yo ds, 5yo ds, and 1yo ds

4th year with MFW
Using:
MFW 1st w/ 7yo ds
MFW RtR w/ 7th grade ds
MFW World History with 10th grade dd
So far we have used: ECC, 1850-Present, CTG, RtR, High School Ancients and MFW K

Biology lab equipment

Unread post by cbollin » Thu May 19, 2011 12:30 pm

I was happy with our purchase from HomeScience Tools.
http://www.hometrainingtools.com/Default.asp?
They have recommendations on their site for kits for many programs, and a cross comparison list for microscope shopping.

I went with this one
http://www.hometrainingtools.com/home-m . I-4100STD/
and bought the apologia lab kit for it.

you might want to ask around local friends to see if anyone has the slide set just sitting around. or the ability to rent you/loan a microscope. or even the dissection pans and tools.

I was amazed that I was able to get "free specimens" because someone had unopened ones after changing their minds. We did 3 out of 4 (minimum in the apologia book for that portion of lab credit.) So we never did the frog. There was alternative experiment for frog dissection and my oldest just had to skip dissection. Even with her dad being lab partner.

and guess what? I didn't want dead frog in the house. right? what? that specimen totally freaked me out. I had to take anxiety meds on it. It creeped me out. ok. so, I put a notice on local homeschool forum "free frog to cut up. " it was gone within an hour to some mom whose 9 year old son really wanted it.

but, silly me silly story here. b/c I had the free specimens (which you don't have to order until you are closer to module 11), I only ordered dissection tools. Silly me. I forgot the pan! We had to improvise with cardboard and egg cartons and it all worked out.

enjoy the pond water experiment I got our water from a local greenhouse. I had my biology text with me and said "I just need about 16 ounces of really scummy water from bottom of a pond and I"m too scared to cross into private lake across the street." The owner just looked at me and said "ok. over here." LOL

and you'll really think I"m a homeschooler on this one.

early on there is some experiment to grow mold or look at mold from blue cheeses or something. What I should have done, in retrospect, was to just go to the cheese counter at kroger, and take my biology book and ask for sample, or even pay for just a spoon ful of that stuff.

I mean. roquefort cheese isn't cheap, right? ok. so I end up getting the smallest smallest pre cut stuff at the cheese shop at kroger. And guess what? I was able to give the rest away to another family or two doing apologia. Only on homeschooling forums do you post "For Give away: 1 ounce of roquefort cheese. Perfect for apologia biology lab module" and then the week and all of that. yep. gone in less than an hour as well.


Choosing a Microscope

This article is based on material originally published in Illustrated Guide to Home Chemistry Experiments: All Lab, No Lecture, by Robert Bruce Thompson, and the not-yet-published Illustrated Guide to Forensics Investigations: Uncover Evidence in Your Home, Lab, or Basement, by Robert Bruce Thompson and Barbara Fritchman Thompson.

Without a microscope, we are limited to what we can see with the naked eye. Using a microscope reveals entire worlds that would otherwise be invisible to us. Obviously, a microscope is essential for the serious study of biology and forensics. Less obviously, a microscope is also an important tool in disciplines as diverse as chemistry, Earth science, and physics.

Every home scientist should make it a high priority to acquire a good microscope. The question is, which one? This article explains what you need to know to choose a microscope appropriate for your needs and budget.

Price
First, let’s talk about price. Microscopes are available in an incredible range of prices, from $25 toy microscopes to professional models from German and Japanese manufacturers that can cost as much as a new Mercedes-Benz automobile. Literally. Toy models are obviously unsuitable for serious use, but few of our readers will have the inclination (or budget) to spend thousands on a professional model. Fortunately, there’s a happy middle ground of inexpensive, high-quality microscopes that sell in the $150 to $1,200 range. We’ll focus on that category.

All of these microscopes are Chinese-made. The best of the Chinese microscopes are very good, both optically and mechanically. Unfortunately, Chinese factories also produce boatloads of garbage microscopes, and it’s impossible to tell the difference just by looking at the scopes or comparing prices. The best way to get a good one is to buy from a reputable dealer.

Microscope Types
Broadly speaking, two types of microscopes are useful in home science labs. A compound microscope, shown in Figure 1, is what most people think of as a microscope. You use it to view small specimens by transmitted light at three or four medium to high magnifications, typically 40X, 100X, 400X, and sometimes 1000X. A good compound microscope is essential for serious study of biology or forensics, and useful for many other sciences.


Figure 1. A typical compound microscope (image courtesy National Optical & Scientific Instruments, Inc.)

A stereo microscope, shown in Figure 2, uses two eyepieces, each with its own objective lens, to provide a 3D image of the specimen. A stereo microscope (also called a dissecting microscope or an inspection microscope) operates at low magnifications, usually in the 10X to 50X range. Some models have fixed magnification, usually 10X, 15X, or 20X. Other models offer a choice of two magnifications, often 10X or 15X and 30X or 40X. Zoom models offer continuously variable magnification.


Figure 2. A typical stereo microscope (image courtesy National Optical & Scientific Instruments, Inc.)

A stereo microscope is useful for examining relatively large solid objects at low magnification by reflected rather than transmitted light. Most stereo microscopes provide a top illuminator that directs light downward onto the specimen. Better models often also offer a bottom illuminator that allows specimens to be viewed by transmitted light.

For a home lab, a stereo microscope is useful but not essential. Buy one if you can afford it, but don’t skimp on the compound microscope. It’s better to buy a good compound microscope and no stereo microscope than to buy cheap models of each. If you don’t have a stereo microscope, you can substitute a magnifier or pocket microscope, or in some cases simply use your compound microscope at its lowest magnification.

Head Style
Compound microscopes may be available in any or all of the four head styles shown in Figure 3.

  • A monocular head provides only one eyepiece. This is the least expensive of the four head styles, and is suitable for general use.
  • A dual head provides two eyepieces, one vertical and one angled. The second eyepiece allows two people to view a specimen simultaneously, for example a teacher and a student. A dual head is also very convenient if you want to mount a still or video camera to image specimens. Dual head models typically cost $50 to $100 more than comparable monocular models.
  • A binocular head provides two eyepieces to allow viewing specimens with both eyes. One eyepiece is individually focusable to allow the instrument to be set up for one person’s vision. The advantage of a binocular head is that it’s less tiring to use over long periods and may allow seeing more detail in specimens. The disadvantage is that the focusable eyepiece must be adjusted each time a different person wants to use the scope. Binocular models typically cost $150 to $250 more than comparable monocular models.
  • A trinocular head provides two eyepieces for binocular viewing and a separate single eyepiece for viewing by a second person or for mounting a camera. Trinocular models typically cost $300 to $400 more than comparable monocular models.

At any particular price point, a monocular-head model offers the maximum bang for the buck. You’ll get better optical and mechanical quality with the monocular head than with any of the multiple-head models.


Figure 3. Monocular, dual-head, binocular, and trinocular head styles (images courtesy National Optical & Scientific Instruments, Inc.)

Regardless of head style, most better models allow the head to be rotated through 360° to whatever viewing position you prefer. The left image in Figure 3 shows the traditional viewing position, with the support arm between the user and the stage. The other three images show the reversed viewing position, with the stage between the user and the support arm. Most people prefer the latter position, which makes it easier to manipulate slides, change objectives, and so on.

Illumination Type and Power Source
Early microscopes and some inexpensive current models have no built-in illuminator. Instead, they use a mirror to direct daylight or artificial light up through the stage and into the objective lens. Because any mirror small enough to fit under the microscope stage gathers insufficient light to provide bright images at high magnifications, such scopes are limited to use at low and medium magnifications unless they are equipped with an accessory illuminator. Most microscopes include built-in illuminators of one of the following types, roughly in order of increasing desirability:

  • Tungsten – the least expensive method, and the most common on low-end scopes, tungsten illuminators use standard incandescent light bulbs. They are relatively bright, but they produce a yellowish light and considerable heat. In particular as the light is dimmed, it shifts further toward orange. This warm color balance can obscure the true colors of specimens. The heat produced by the incandescent bulb may kill live specimens and quickly dries out temporary wet mounts made with water. Lamp life is relatively short.
  • Fluorescent – costs a bit more than tungsten, and was quite popular before the advent of LED illuminators. Fluorescent illuminators provide bright light that appears white to the human eye, but is actually made up of several different discrete colors that are mixed to appear white. Accordingly, color rendition can differ significantly from the true color rendition provided by daylight. Fluorescent bulbs emit much less heat than incandescent bulbs, and so are well suited to observing live specimens. Some fluorescent illuminators are battery-powered, but most use AC power. Lamp life is relatively long.
  • LED – priced about the same as fluorescent illuminators, LED illuminators have become very popular, largely replacing fluorescent illuminators. LED illuminators have the same color-rendition problems as fluorescent illuminators, but are otherwise ideal for many purposes. LED illuminators draw very little power and emit essentially no heat. Their low power draw means they’re the best choice for a battery-powered microscope, and are ideally suited for portable microscopes that can be used in the field. Lamp life is essentially unlimited.
  • Quartz-halogen – the most expensive type of illuminator, and the one preferred by most microscopists. They provide a brilliant white light needed for work at high magnification that reveals the true colors of specimens. Unfortunately, quartz-halogen lamps also produce more heat than any other type of illuminator. Their high power draw means they are AC-only. Lamp life is relatively short.

Choose quartz-halogen if it is available for the scope model you purchase. Otherwise, choose LED. Tungsten is appropriate only for an entry-level scope.

Nosepiece, Objectives, and Ocular (Eyepiece)
The nosepiece, also called the turret, is a rotating assembly that holds 3, 4, or (rarely) 5 objective lenses. By rotating the nosepiece, you can bring any a different objective lens (usually just called an objective) into position and change the magnification you use to view the specimen. Inexpensive microscopes use friction-bearing nosepieces better models use ball-bearing nosepieces with positive click-stop detents. Figure 4 shows a typical nosepiece with three objectives visible.


Figure 4. A typical microscope nosepiece with objective lenses

The nosepiece may be mounted in the forward position (tilted away from the support arm) or reverse position. If you use the scope in the forward viewing position (with the support arm between you and the stage), having the nosepiece mounted in the forward position makes it a bit easier to change objectives. If you use the reverse viewing position, it’s easier to use a nosepiece mounted in the reverse position.

Objective lenses are usually color-coded to make it obvious which one is currently being used. The standard color codes are red (4X), yellow (10X), green (20X), light blue (40X or 60X), and white (100X). Not all manufacturers follow this standard.

Inexpensive microscopes usually provide three objective lenses, 4X, 10X, and 40X. Better microscopes usually include a fourth, 100X, objective lens. The overall magnification of the microscope is the product of the objective lens magnification factor and the eyepiece (ocular) magnification factor. So, for example, if your microscope has a 10X eyepiece and 4X, 10X, and 40X objectives, your available magnifications are 40X, 100X, and 400X. If you also have a 100X objective, you also have 1000X magnification available. If you replace the standard 10X eyepiece with a 15X eyepiece, your available magnifications become 60X, 150X, 600X, and 1500X, which is about the maximum magnification usable with an optical microscope.

Microscope objective lenses differ in two major respects, color correction and flatness of field.

Finally, some vendors offer optional upgrades to superior lens coatings, often under such names as Super High Contrast or something similar. These superior coatings don’t improve color correction or flatness of field, but they increase image contrast noticeably.

For most home lab use, ordinary achromatic objectives provide perfectly acceptable images and are by far the least expensive choice. My own microscope, a Model 161 dual-head unit shown in Figure 3, has the upgraded ASC objectives, which I purchased because I planned to do a lot of photography through the microscope. Otherwise, I’d have bought the standard achromatic objectives.

Parfocality and Parcentrality
All but toy microscopes are parfocal and parcentered. Parfocal means that all objectives have the same focus. When you focus a specimen at 40X, for example, and then change to 100X, the specimen remains focused. (You may have to touch up the focus with the fine-focus knob, but the focus should be very close to start with.) Parcentered means that if you have an object centered in the field of view with one objective and you change to a different objective, the object remains centered in the field of view. Professional-grade microscopes provide adjustments for both parfocality and parcentrality, but student- and hobbyist-grade microscopes are set at the factory and cannot be adjusted by the user. That means it’s important to check these settings as soon as you open the box of your new microscope.

To check parfocality, place a flat specimen (a thin-section or smear slide is good, if you have one otherwise any flat specimen) on the stage and focus critically on it at the lowest magnification. Then change to your next highest magnification and check the focus. It should be in focus or nearly so, requiring at most a partial turn of the fine-focus knob to bring it into critical focus. Change to your next higher magnification and again check the focus. Again, it should require at most a small tweak with the fine-focus knob to bring the specimen into sharp focus.

To check parcentrality, center an object in the field of view at the lowest magnification and then switch objectives to the next-higher magnification. The object should remain centered, or nearly so. Repeat until you are viewing the object at your highest magnification. Because it’s easier to judge whether an object is centered at high magnification, center the object at your highest magnification and then work your way down to lower magnifications. If the object remains centered (or nearly so), your parcentrality is acceptable. If the position of the object in the field of view shifts dramatically when you change objectives, the parcentrality is off. The only solution is to return the microscope for a replacement. (All of the scopes sold by Maker Shed are manually checked for parfocality and parcentrality before shipping and should be fine unless they are damaged in shipping, which very rarely happens.)

The ocular (or eyepiece) magnifies and focuses the image provided by the objective lens and presents it to your eye. Standard microscope ocular barrels are either 23.2 mm (usually abbreviated to 23 mm) or 30 mm in diameter, which means it’s easy to exchange oculars if you need a different magnification range. The standard ocular magnification factor is 10X, but 15X oculars are readily available to increase the range of magnifications available to you. Avoid zoom oculars, which invariably produce inferior images.

Most toy microscopes have single-element oculars, sometimes made of plastic, that provide a distorted, dim, narrow view. Better microscopes, including all of the models offered by Maker Shed, provide multi-element optical glass oculars that provide a flat, bright, wide field of view with minimal distortion.

Most standard oculars are unobstructed, but some have a standard or optional pointer or reticle (grid or graduated scale). A pointer is primarily useful in a teaching or collaborative environment, where one person can place the pointer on an object of interest so that the other person can identify it unambiguously. A graduated reticle is useful in biology and forensics for measuring the size of objects in the field of view, and a grid reticle is useful for counting large numbers of small objects in the field of view.

Focusing
Microscopes use one of two methods for focusing. Most older models and some current models keep the stage in fixed position and move the head up and down to achieve focus. Most current models and some older models reverse this, keeping the head in a fixed position and moving the stage up and down to achieve focus. Either method works well.

Toy microscopes and the least expensive hobby/school models have a single focus knob that changes focus at intermediate rate, which makes it difficult to achieve critical focus. Midrange models have separate coarse-focus and fine-focus knobs. More expensive models usually have a coaxial focus knob, often one one each side of the microscope, with the coarse focus on the outer knob and the fine focus on the inner knob, as shown in Figure 5.


Figure 5. Coaxial focusing knob, with coarse focus (outer ring) and fine focus

You use the coarse-focus knob to bring the specimen into reasonably close focus, and then use the fine-focus knob to tweak the focus slightly to achieve the sharpest possible focus. If you are viewing a three-dimensional object, particularly at higher magnifications, you’ll find that you can’t bring the entire depth of the object into focus at the same time. You use the fine-focus knob to adjust focus slightly as you’re viewing the object to view different “slices” of it in depth.

Many coaxial focus knobs, including the one in Figure 5, provide a graduated scale. One obvious use for this scale is in a collaborative situation. One person can focus critically, note the scale setting, and then turn over the microscope to the second person, who refocuses as necessary. When the first person returns to the eyepiece, merely resetting the scale to the original value puts the specimen back into critical focus. A less obvious use of the graduated scale is to determine relative depths of parts of a specimen. By setting a baseline focus on one level of the specimen and then noting how much change in scale units is needed to refocus on parts of the specimen at different depths, you can get a relative idea of the differences in depth of different parts of the specimen.

Mechanical Stage
Inexpensive microscopes use a pair of clips to secure the microscope slide to the stage. Although workable at low magnifications, this method becomes increasingly difficult as you increase magnification. The problem is that a very small movement of the microscope slide translates into a huge movement in the field of view. At low magnification, the smallest movement you can make manually may move an object from one side of the field of view to the other. At higher magnifications, the smallest movement you can make manually may move the object completely out of the field of view. If you’re viewing a living, moving object (such as a paramecium), it can be almost impossible to keep the object in the field of view.

The solution to this problem is a mechanical stage, shown in Figure 6. With a mechanical stage, you clamp the slide into an assembly that provides rack-and-pinion gearing that allows you to turn knobs to move the slide continuously along the X-axis (left or right) and the Y-axis (toward or away from you) in extremely small small increments.


Figure 6. A typical mechanical stage (note the verniers on the X and Y axes and the top lens of the Abbe condenser below the stage)

Centering an object becomes trivially easy, as does keeping a moving object in the field of view. Because the mechanical stage provides X-axis and Y-axis verniers, it’s easy to return to a specific location on the slide even after you’ve moved it completely outside the field of view. We wouldn’t even consider using a microscope without a mechanical stage. Life is too short.

Substage Components
Despite the fact that they’re located below the stage (and therefore below the specimen), two substage components have a significant effect on image quality.

Diaphragm
The diaphragm is used to control the diameter of the light cone where it intersects the specimen being viewed. Ideally, you want the diameter of the light cone to be the same size as the field of view of the objective lens you’re using. At low magnification, where the field of view is relatively large, you want a larger light cone at higher magnification, where the field of view becomes correspondingly smaller, you want a smaller light cone. If the light cone is smaller than the field of view, the field is not completely illuminated. If the light cone is larger than the field of view, “waste” light from outside the field of view reduces contrast and image quality.

Toy microscopes have no diaphragm. Basic models have a disc diaphragm, which is simply a metal disc with several (usually five or six) holes of different diameter that can be rotated into position. Disc diaphragms provide only compromise settings, but are generally quite usable. Better microscopes have iris diaphragms, which can be set continuously to provide any size of aperture, from a pinhole to wide open.

Condenser
The condenser sits between the diaphragm and the stage, focusing light from illuminator onto the specimen to provide a brighter, sharper image. Toy microscopes and entry-level student/hobbyist microscopes have no condenser. Somewhat better microscopes use a simple fixed-focus condenser, usually rated at 0.65 NA (Numerical Aperture, where the NA of the condensor must be at least as high as the NA of the objective lenses it is to be used with. A 0.65 NA condenser can be used with at most a 40X objective. Oil-immersion 100X objectives with a 1.25 NA rating require a 1.25 NA condenser.) Midrange microscopes use a focusable Abbe condenser, usually of 0.65 NA and usually with a spiral focusing arrangement. Better models provide a rack-and-pinion focusable Abbe condenser with a 1.25 NA for use with any objective up to a 100X oil-immersion objective.

Köhler Illumination
If you pick up any book on basic microscopy, you’ll soon encounter the term Köhler illumination. Devised by August Köhler in 1893, this illumination method provides extremely even illumination and the highest possible contrast. Unfortunately, setting up Köhler illumination requires physical features not present on affordable scopes, including a positionable lamp and a focusable lamp condenser. Very few microscopes under $1,000 include the features needed to set up Köhler illumination.

Fortunately, the alternative, called critical illumination, is perfectly usable for most visual work. (In fact, many experienced microscopists prefer critical illumination to Köhler illumination for visual work at high magnification.) The extreme evenness of Köhler illumination is important for professional quality results when you shoot images through a microscope, but otherwise critical illumination works fine.

The Final Decision
So, with all of that said, which model should you get? Obviously, that depends on both your needs and your budget, but we can offer some advice to help you make a good decision.

[Editor’s Note: the following products are no longer carried at makershed.com.]

Entry Level 400X microscope:
It’s as easy to spend too little on a microscope as it is to spend too much. We suggest you avoid toy microscopes entirely. They’re a waste of money. If you need a basic 400X scope at minimal cost, choose the Maker Shed Model 109. This scope is perfect for undemanding hobby use or for elementary school students, and in a pinch, can serve through middle school. At $119, it lacks a mechanical stage and provides only basic features, but the optics and mechanicals are solid.

Midrange 400X scope:
If you need a midrange 400X scope, choose the Maker Shed Model 131. This scope is good for hobby use, and can serve a student from middle school or junior high school through high school, excepting AP biology. At $235 this scope provides very good optics and mechanicals. The only major missing feature is the 100X oil-immersion objective, which is needed for cell biology studies in high school AP biology courses.

Entry Level 1000X scope:
If you need an entry-level 1000X scope, choose the Maker Shed Model 134. This scope is excellent for hobby use, and is the only scope a student will need from middle school or junior high school through high school AP biology. At $359, this scope provides very good optics and mechanicals, and is essentially a Model 131 upgraded to include a 100X oil immersion objective, a focusable 1.25 NA Abbe condenser, an iris diaphragm, and a standard mechanical stage.

“Lifetime” 1000X scope:
If you want to make your first microscope purchase your last, choose one of the Maker Shed 160-series models, the $479 Model 160 (monocular), $539 Model 161 (dual-head), $629 Model 162 (binocular), or $819 Model 163 trinocular). You can pay a lot more for a microscope, of course, but the only major feature missing from the 160-series scopes is support for Köhler illumination. Any of the 160-series microscopes is a superb choice for hobby use, and is the only scope a student will need from middle school or junior high school all the way through university and graduate school. The optics and mechanicals are excellent, and the feature list is impressive. Even people who use professional-grade microscopes every day are invariably stunned by the level of mechanical and optical quality the 160-series microscopes provide at this price point. The only upgrades we offer on these scopes are the ASC (high contrast) or plan achromatic objectives.


My First Lab Duo-Scope

"Bargain Books" are brand new items that have minor physical blemishes due to shipping or handling that do not affect the use of the item. All Bargain Books are sold as is and all sales are final (no returns, exchanges or cancellations). Bargain books will remain in shopping cart for up to 12 hours and will then be removed if order is not completed. Orders consisting of regular and Bargain items can be purchased by credit card or PayPal and are shipped together (with two packing slips).

This item is a digital download file and is not a printed or physical product. Upon completion of checkout, you will receive an email with a link for you to download the file and save to your local device. Please note that ebooks and other digital media downloads are not returnable and all sales are final.

Product Description:

What a great starter scope! Many of the features you'll find on a more expensive scope are now available for the young scientist. This battery operated (3 AA batteries are not included) microscope has:

  • rotatable nosepiece with 4X, 10X, and 40X objectives
  • 10X widefield eyepiece on an inclined head
  • 6 hole disc diaphragm
  • real optical glass lenses
  • 3 " x 3 " stage with spring mounted stage clips
  • coarse focus knob
  • dual LED lights
  • powder-coated metal construction with sturdy plastic base

View slides using the light below and solid objects with the upper light. You won't find this feature on any of our other microscopes. See slides up to a 400X magnification and solid objects up to 100X magnification. Look closely and you'll be able to see Abraham Lincoln sitting in his memorial on the back of the penny!

This microscope comes with a nice accessory set which includes: 5 blank slides, 4 prepared slides, 1 concave slide, cover glass, pipette, forceps, lens paper, small plastic test tube, small plastic Petri dish, and red and blue dye. A 10-page users manual explains how to prepare slides, operate the microscope, and offers suggestions for observation.

The LED lights burn longer and cooler than incandescent lighting, so no chance of little fingers getting hot. An automatic stage stop is helpful in keeping the objectives from touching the slides however, it doesn't work well with the 40X objective. This objective is longer and the stage doesn't stop soon enough before putting pressure on the slide. You'll also notice that there is no 'fine focus' knob. I thought that would be a problem getting things in focus, but really had very little difficulty. I looked at several slides and objects on all of the settings of this microscope. I'm really impressed with the features offered for such a low price.

If you're not sure which microscope best fits your needs, check out our Microscope Comparison Sheet for a side-by-side comparison of all microscope models we offer.

Publisher Description:

The Duo Scope is our most popular microscope in the My First Lab series! Designed with two light sources, this microscope can magnify both slides and solid objects. View slides, coins, plants, stamps, insects, jewelry, and more!

No longer do you need one basic biological microscope to look at specimens on a slide (light shines up from under the slide and through the tissue) and a traditional stereo or dissecting microscope to view solid objects (light shines down onto the specimen to be observed). Instead, equipped with dual lighting, the Duo Scope allows for both applications!

  • Supports STEM (science, technology, engineering, and math) learning and fun!
  • 40x, 100x and 400x
  • Laboratory-grade glass lenses
  • 2 LED lights, above and below the stage
  • Uses 3 AA batteries (not included)

Cordless battery power makes it possible for kids to take this microscope into the field. Portability, combined with durability, makes for a perfect option for explorers! This microscope is an affordable, high-quality option for your STEM-focused child!


Staining Onion Cells

Since onion peels are translucent,

you’ll need to stain the onion cells before you observe them under the microscope.

There are different types of stains depending on what type of cell you are going to look at.

  • Iodine– dark stain that colors starches in cells. In an onion cell, it will make the cell wall more visible. It provides some contrast for viewing under a microscope.
  • Methylene Blue– a blue stain that will color blood, bacteria, acidic or protein rich cell structures like nucleus, ribosomes, and endoplasmic reticulum.
  • Eosin Y– a pink or red stain that colors blood, plants, and alkaline animal cell structures like the cytoplasm.

The Microscopic Life Kit from Home Science Tools contains both Eosin Y and Methylene Blue for staining many types of cells.


Bright Field Microscopy

With a conventional bright field microscope, light from an incandescent source is aimed toward a lens beneath the stage called the condenser, through the specimen, through an objective lens, and to the eye through a second magnifying lens, the ocular or eyepiece. We see objects in the light path because natural pigmentation or stains absorb light differentially, or because they are thick enough to absorb a significant amount of light despite being colorless. A Paramecium should show up fairly well in a bright field microscope, although it will not be easy to see cilia or most organelles. Living bacteria won't show up at all unless the viewer hits the focal plane by luck and distorts the image by using maximum contrast.

A good quality microscope has a built-in illuminator, adjustable condenser with aperture diaphragm (contrast) control, mechanical stage, and binocular eyepiece tube. The condenser is used to focus light on the specimen through an opening in the stage. After passing through the specimen, the light is displayed to the eye with an apparent field that is much larger than the area illuminated. The magnification of the image is simply the objective lens magnification (usually stamped on the lens body) times the ocular magnification.

Students are usually aware of the use of the coarse and fine focus knobs, used to sharpen the image of the specimen. They are frequently unaware of adjustments to the condenser that can affect resolution and contrast. Some condensers are fixed in position, others are focusable, so that the quality of light can be adjusted. Usually the best position for a focusable condenser is as close to the stage as possible. The bright field condenser usually contains an aperture diaphragm, a device that controls the diameter of the light beam coming up through the condenser, so that when the diaphragm is stopped down (nearly closed) the light comes straight up through the center of the condenser lens and contrast is high. When the diaphragm is wide open the image is brighter and contrast is low.

A disadvantage of having to rely solely on an aperture diaphragm for contrast is that beyond an optimum point the more contrast you produce the more you distort the image. With a small, unstained, unpigmented specimen, you are usually past optimum contrast when you begin to see the image.

Using a bright field microscope

First, think about what you want to do with the microscope. What is the maximum magnification you will need? Are you looking at a stained specimen? How much contrast/resolution do you require? Next, start setting up for viewing.

Mount the specimen on the stage

The cover slip must be up if there is one. High magnification objective lenses can't focus through a thick glass slide they must be brought close to the specimen, which is why coverslips are so thin. The stage may be equipped with simple clips (less expensive microscopes), or with some type of slide holder. The slide may require manual positioning, or there may be a mechanical stage (preferred) that allows precise positioning without touching the slide.

Optimize the lighting

A light source should have a wide dynamic range, to provide high intensity illumination at high magnifications, and lower intensities so that the user can view comfortably at low magnifications. Better microscopes have a built-in illuminator, and the best microscopes have controls over light intensity and shape of the light beam. If your microscope requires an external light source, make sure that the light is aimed toward the middle of the condenser. Adjust illumination so that the field is bright without hurting the eyes.

Adjust the condenser

To adjust and align the microscope, start by reading the manual. If no manual is available, try using these guidelines. If the condenser is focusable, position it with the lens as close to the opening in the stage as you can get it. If the condenser has selectable options, set it to bright field. Start with the aperture diaphragm stopped down (high contrast). You should see the light that comes up through the specimen change brightness as you move the aperture diaphragm lever.

Think about what you are looking for

It is a lot harder to find something when you have no expectations as to its apprearance. How big is it? Will it be moving? Is it pigmented or stained, and if so what is its color? Where do you expect to find it on a slide? For example, students typically have a lot of trouble finding stained bacteria because with the unaided eye and at low magnifications the stuff looks like dirt. It helps to know that as smears dry down they usually leave rings so that the edge of a smear usually has the densest concentration of cells.

Focus, locate, and center the specimen

Start with the lowest magnification objective lens, to home in on the specimen and/or the part of the specimen you wish to examine. It is rather easy to find and focus on sections of tissues, especially if they are fixed and stained, as with most prepared slides. However it can be very difficult to locate living, minute specimens such as bacteria or unpigmented protists. A suspension of yeast cells makes a good practice specimen for finding difficult objects.

  • Use dark field mode (if available) to find unstained specimens. If not, start with high contrast (aperture diaphragm closed down).
  • Start with the specimen out of focus so that the stage and objective must be brought closer together. The first surface to come into focus as you bring stage and objective together is the top of the cover slip. With smears, a cover slip is frequently not used, so the first thing you see is the smear itself.
  • If you are having trouble, focus on the edge of the cover slip or an air bubble, or something that you can readily recognize. The top edge of the cover slip comes into focus first, then the bottom, which should be in the same plane as your specimen.
  • Once you have found the specimen, adjust contrast and intensity of illumination, and move the slide around until you have a good area for viewing.

Adjust eyepiece separation, focus

With a single ocular, there is nothing to do with the eyepiece except to keep it clean. With a binocular microscope (preferred) you need to adjust the eyepiece separation just like you do a pair of binoculars. Binocular vision is much more sensitive to light and detail than monocular vision, so if you have a binocular microscope, take advantage of it.

One or both of the eyepieces may be a telescoping eyepiece, that is, you can focus it. Since very few people have eyes that are perfectly matched, most of us need to focus one eyepiece to match the other image. Look with the appropriate eye into the fixed eyepiece and focus with the microscope focus knob. Next, look into the adjustable eyepiece (with the other eye of course), and adjust the eyepiece, not the microscope.

Select an objective lens for viewing

The lowest power lens is usually 3.5 or 4x, and is used primarily for initially finding specimens. We sometimes call it the scanning lens for that reason. The most frequently used objective lens is the 10x lens, which gives a final magnification of 100x with a 10x ocular lens. For very small protists and for details in prepared slides such as cell organelles or mitotic figures, you will need a higher magnification. Typical high magnification lenses are 40x and 97x or 100x. The latter two magnifications are used exclusively with oil in order to improve resolution.

Move up in magnification by steps. Each time you go to a higher power objective, re-focus and re-center the specimen. Higher magnification lenses must be physically closer to the specimen itself, which poses the risk of jamming the objective into the specimen. Be very cautious when focusing. By the way, good quality sets of lenses are parfocal, that is, when you switch magnifications the specimen remains in focus or close to focused.

Bigger is not always better. All specimens have three dimensions, and unless a specimen is extremely thin you will be unable to focus with a high magnification objective. The higher the magnification, the harder it is to "chase" a moving specimen.

Adjust illumination for the selected objective lens

The apparent field of an eyepiece is constant regardless of magnification used. So it follows that when you raise magnification the area of illuminated specimen you see is smaller. Since you are looking at a smaller area, less light reaches the eye, and the image darkens. With a low power objective you may have to cut down on illumination intensity. With a high power you need all the light you can get, especially with less expensive microscopes.

When to use bright field microscopy

Bright field microscopy is best suited to viewing stained or naturally pigmented specimens such as stained prepared slides of tissue sections or living photosynthetic organisms. It is useless for living specimens of bacteria, and inferior for non-photosynthetic protists or metazoans, or unstained cell suspensions or tissue sections. Here is a not-so-complete list of specimens that might be observed using bright-field microscopy, and appropriate magnifications (preferred final magnifications are emphasized).


Watch the video: 5 Μυστικά Για Να Τον Κάνεις Να Τρέχει Από Πίσω Σου (December 2022).