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Record the results of your experiments in the tables below.
A. Pouring plates:
Observe that your plates were poured properly--the bottom of the petri dish should be about half full and the media should be sterile, even, and contain few or no bubbles.
B. Aseptic transfers
Look for turbidity in the broth indicating growth of microorganisms. Record the turbidity of the Nutrient broth in the three tubes as + or -. Recall what your sterile Nutrient broth looked like before it was inoculated.
Nutrient broth tube
Turbidity + or -
Also note any other distinguishing characteristics (amount and location of turbidity, color, etc.) of the bacterial growth in the broth and note and record any differences between species of bacteria. An effective method for recording your results is to draw a picture of the tube and the appearance of the broth due to any growth.
C. Streak Plates
1. Check to see whether you obtained well-isolated single colonies on the agar streak plates. Describe and compare your results for each inoculum.
From Broth: Describe growth characteristics and make a sketch in the circle below.
From Agar: Describe growth characteristics and make a sketch in the circle below.
Based on your results, answer the following questions:
2. Were you able to separate and identify the two different bacterial species in your "mixed culture"?
3. Colony morphology can be an aid in the identification of microorganisms.
Although colony morphology cannot be employed as the sole identifying criterion, it is a useful trait in the classification of many common types of microorganisms. Five parameters are normally used to describe microbial colonies growing on an agar surface.
a. Size: pinpoint, small, medium, or large; range: < l mm - 3cm
b. Color: absolutely white, various degrees of pigmentation
c. Texture: the texture of the colony as determined by touching the colony
with a needle; smooth (buttery), dry (granular), or mucoid (slimy) and the
appearance as judged by the manner in which the colony refracts light;
clear, glistening, dense, opaque, or translucent.
d. Form: the shape of the colony; circular, irregular, filamentous, or rhizoid
(see Figure 1 -7)
e. Elevation: the degree to which colony growth is raised; flat, raised,
convex or umbonate (see Figure l-7)
f. Margin: the shape of the edge or margin of the colony (see Figure below)
Image 1: Different colony morphologies/characteristics
Compare your bacterial colonies to those of your bench mates. Note and record any differences in the way various bacterial species grow on agar surfaces.
D. Ubiquity of Microorganisms
Do not throw these test plates away until you have read Exercise 2, part D ("test plate isolate”).
Check to see if your "sterile control" plates remained sterile and were not contaminated. Observe, record, and DESCRIBE the numbers and varieties of different microbial colonies that appear on your test plate. Indicate the sample source (finger plate or other) or exposure method for the test plate.
"test plate" and source:
2.5: Results - Biology
Writing the Results Section
(printable version here)
This is the section in which you will want to present your findings to the reader in the most clear, consistent, orderly, and succinct fashion. As previously mentioned, we suggest that you write this section either first or second to the Materials and Methods section. Another possibility is that you could write them simultaneously, describing each experiment and the corresponding data. Whatever you find easiest is fine.
The results you collect will most likely contain a story that you want to tell to the reader in an interesting manner. Presenting these data in a clear and thorough fashion, however, is quite a responsibility, because you have many decisions to make as to how you want to tackle the ominous task. It must be done well, because without the results being understood, the credibility of the entire paper disintegrates before the reader's eyes. The task is a manageable one, provided that you sit down and think logically about what needs to be made unequivocally clear. By this we mean that common sense goes a long way. Include only what is necessary, and don't include extraneous information. If there is a datum that is important to the ultimate conclusion but is difficult to present, you must find a way to do it. Do not think that you can sweep some pertinent data under the rug and expect to get away with it. If something important is missing, the omission will stare the reader viciously in the face and he or she will be lost. Be sensible, include what you feel needs to be included, and do it in a clear and understandable way, for the results are the primary ingredients upon which your entire paper is based.
Methods for Presenting Data
The ways of presenting data vary depending upon what you want to present to the reader. The Results section should include all of the experimental data collected throughout the experiment that was necessary in reaching the ultimate conclusions drawn. This includes tables, graphs, Western blots, SDS-PAGE results, etc. Each set of data requires a logically selected label (e.g. Figure 1 or Table 1) and a descriptive title referring to the nature of the experiment. A brief paragraph of explanation should be included for each table or figure as well so that the reader knows exactly what he or she is looking at. Graphs and tables require some discretion in terms of what needs to be included and what doesn't.
You have to decide for yourself what information is essential for the reader's understanding of the paper, but do it carefully. Not enough information can confuse and lose the reader, but too much information can become monotonous for the reader. As a general rule, raw data does not need to be included it should be formed into some sort of graph whether that be a line graph, a bar graph, a pie graph, or whatever you feel is necessary to point out the important trends that help tell your story you decide what the data calls for. Then, the proper labels must be assigned to each axis if you choose to use a bar or a line graph. Also with graphs, the standard deviation for each datum will sometimes be required by your professor. Without the level of error provided, the reader has no idea how consistent your findings are. However, in a laboratory class, often you will not obtain the data to calculate the standard deviation. It will depend on your professor and the experiment being performed. Also, (just like every other table, picture, or graph) an explanatory paragraph must be included to guide the reader along.
General guidelines for writing the results section
1. Do not be ambiguous. Do not make the reader guess at what information you are trying to present.
2. Organize the data in a logical fashion. The reader must be able to follow the flow of the data otherwise, the paper will mean nothing and most likely frustrate the reader.
3A. Do not describe methods used to obtain the data. This belongs in the Materials and Methods section.
3B. Do not attempt to interpret the data. This belongs in the Discussion section
4. Point out certain trends or patterns that the data follow. Data is organized in a manner that will point out trends that you want to make clear to the reader in order to help tell your story. You must call the reader's attention to these trends or they may be missed.
The following data includes two tables and two figures to demonstrate the points explained above. Each table or figure has a description of what is appropriate or what needs improvement.
Review of Sample 1: There are many problems with the presentation of this table, forcing the reader to guess about some of the data. First, it is not labeled as either a table or a figure. It is simply given a title (Protein Values) that doesn't even describe anything. Protein values of what and under what circumstances? The reader has no idea what he or she is looking at. Also, the column labels don't have the units of measurement included. The absorbance values mean nothing if the reader doesn't know at what level they were taken, and what does protein mean in the third column? Is that concentration, and if so, what are the units? All of these things need to be included to make clear to the reader what the data is.
Table 1. Absorbance Readings and Corresponding Protein Concentration values
|Experimental group||Absorbance (595nm)||Protein Concentration (micg/micl)|
This table demonstrates the protein concentration of each sample. The concentration of protein found in each sample is similar.
Review of Sample 2: This table is properly labeled Table 1, because it is the first table that appears in the paper, and it also has a descriptive title. All of the columns are clearly labeled with the unit of measurement for each one. Also note that there is a brief sentence describing what the numbers are and where they came from.
Figure One shows the absorbance values compared to the times of each tube in the experiment.
Review of Sample 3: There are two problems with the graph itself: neither axis contains the proper unit of measurement labels, and the none of the lines are marked as to what test tube each represents. As with the table in the previous example, the reader needs to know what level of absorbance the results were taken at. Also, the reader has no idea what the lines mean, because he or she has no idea which goes with each tube. Another problem with this figure is that the explanatory sentence is quite scanty. The author doesn't guide the reader along as to what results are being presented. Trends should be pointed out.
Figure One shows the absorbance values (read at 540 nm) of each of the three experimental tubes compared to the time in seconds. This is an indication of the rate that catechol is being turned into benzoquinone in each tube. In the group that the acidity was increased (tube 2), we see a steady increase in absorbance, then a slight dropoff, and then it regained its initial rate of increase. In the control group (tube 3), we see a gradual increase in absorbance values over time, and then it seems to level off. In the group that the amount of the enzyme was increased (tube 4), we see a very slim, but noticeable, increase in absorbance values over the first three seconds.
Review of Sample 4: In this version of Figure One, the proper labels are on both the axes and the three curves. Also, the explanatory paragraph is much more descriptive and informative-it tells the reader what occurring in each of the three tubes and points out specific trends in each of the three curves.
All citations from Pechenik, Jan A. A short guide to writing about Biology. pp. 54-102, Tufts University: Harper Collins College Publishers. 1993.
Pearson digital solutions support and extend teaching and learning in pursuit of defined learner outcomes. This searchable collection of case studies documents implementation results and educational best practices in a range of learning environments. Browse educator-provided evidence below. Learn more about how you can share your results. Not seeing any results below? Load the results
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Mastering Biology educator study looks at required and extra credit homework
Santa Rosa Junior College
Students reported Mastering helped them do better in the course and the results showed that the group with above average Mastering performance had a higher exam average.
Mastering Biology Impact Evaluation Study
Impact Evaluation study (PDF)
This study was conducted by Pearson's Impact Evaluation Team as part of their efficacy reporting. In Spring 2017, Pearson set out to investigate the relationship between the use of Mastering Biology and academic performance. After conducting research with 106 students at a large four-year state university in Texas, researchers found that averaging 90% or better on their Mastering homework assignments was associated with a 9% increase in their exam scores.
Spotlight on Mastering Implementation: How can cheating on Mastering homework be addressed?
What best practices should be implemented to address cheating? How can you implement homework to motivate students to work the problems themselves? This spotlight includes research-based strategies designed to provide guidance to educators when needed.
Spotlight on Mastering Implementation: What if exam scores aren't reflective of homework scores?
If correlations between required Mastering homework scores and exam performance are not strong, first try to understand why. The initial thought may be that students are cheating on homework. While that can be the case, it is not the only reason that can happen as demonstrated by the examples shared in this spotlight.
Spotlight on Mastering Implementation: How can students be held accountable for coming to class prepared?
Find out how instructors can implement pre-lecture assignments in Mastering to prepare for class. Said one educator, "Since adoption of Mastering Biology and implementation of pre-lecture homework assignments, students are noticeably more engaged during lectures, and classes are more interactive.”
Special Interest Article on Planning Your Technology Implementation
Research demonstrates that technology-enhanced instruction can both increase student learning outcomes and lead to greater efficiencies in costs and other resources. As more instructors adopt educational technology, it is important that they understand how to implement the technology to achieve their desired goals.
Special Interest Article on Active Learning: Engaging Distracted Students in the Classroom
Do you struggle with students who are more focused on their tablets than what’s happening in the classroom? Do you see students with a death grip on their phones trying to sneak glances as you lecture? Do you feel like you are competing with a digital device for a student’s attention? This article discusses active learning strategies to address those issues, along with examples of how instructors have implemented Mastering and Learning Catalytics as part of a redesign to more active learning.
MasteringBiology Educator Study - University of Essex
University of Essex
Mastering Biology has been in place at the University of Essex (UK) for over 7 years and throughout that time the lecturer Louise Beard has developed a bank of evidence assessing its impact on her module, on her students grades and their experience. This Educator Study presents key findings around the impact Mastering Biology had on attainment, experience and engagement during that time and, more specifically, for the students who completed the module in 2016.
Mastering Biology educator study reports on redesign
The department started a redesign in 1999 and continued to evaluate results, monitor course costs, and stay up-to-date with educational technology, resulting in ongoing course changes to enhance learning. From 2010 to 2015, the group of students who had Mastering Biology homework scores above the mean had higher final exam averages than students who had lower Mastering homework scores.
Using different Mastering resources to engage students
The instructor used different resources and types of assignments in Mastering to engage and provide multiple learning opportunities for students. These included Dynamic Study Modules for pre-lecture, Tutorials, and Adaptive Follow-Up assignments.
2016 Science and Engineering Report with Educator Case Studies and Implementation Worksheets
The 2016 Science and Engineering Report combines the three-phase approach of Pearson’s Ten Steps to a Successful Implementation, along with 21 educator case studies, to create a framework to help faculty plan and integrate technology into their course. It includes worksheets for each step and examples of how other faculty have implemented technology.
Successful implementation of Mastering across all course formats
Minneapolis Community and Technical College
Evidence from this study showed that the students who did better in the course had attempted more Mastering Biology assignments and had a higher rate of testing out of or scoring 100 percent on personalized Adaptive Follow-Up assignments.
Flipped Learning Implementation Strategies for High Impact
This report includes six implementation and results case studies in which a Flipped Learning model is being used successfully by instructors in a variety of disciplines utilizing MyLab, Mastering or Revel.
Higher Exam scores when more Mastering homework is attempted
Laura Almstead and Becky Miller
University of Vermont
Controlling for variables that influence a student’s exam score, results show that students who attempted more MasteringBiology assignments showed a significant trend towards higher exam scores.
Mastering Biology educator study
After implementing Mastering Biology as part of a four-year course redesign to a flipped classroom, students earned more As and Bs and earned higher average final exam scores.
Higher exam scores and positive student feedback after implementing Adaptive Follow-Up
When Adaptive Follow-Up was added, there was a statistically significant increase in end-of-semester student exam scores.
Science and Engineering Mastering Report 2015
The Science and Engineering v.5 report features 12 data-driven case studies from both two- and four-year schools, along with research and statistics on current educational topics: student engagement, identifying at-risk students, Adaptive Learning, and flipping the classroom.
Mastering homework participation as an indicator of course success
University of Hawaii at Manoa
Students who consistently attempt the MasteringBiology homework tend to have significantly higher exam scores than students who skip the assignments.
Mastering Science and Engineering Report, v. 4
A compendium of 47 studies quantifying Mastering's impact on teaching, learning, and retention. The studies illustrate the variety of ways instructors have used Mastering and the results they have achieved.
Increasing Student Success Using Online Quizzing in Introductory (Majors) Biology
Through detailed, statistical analysis, the benefit of quizzing is demonstrated to be significant for students of diverse academic abilities. Pre-exam quizzing using Mastering is an effective way to increase student performance on exams and allows class time to be utilized for teaching activities.
Increased success with Prelecture Assignments
State University of New York - College of Environmental Science and Forestry
Students come to class better prepared and are more engaged after doing prelecture assignments in MasteringBiology. As a result, student success rates are significantly higher.
Unit 4 - Identifying Anomalous Results
Following the practical work in your experiment, the next step is identifying any anomalous results. In this GCSE Biology quiz we look at the effects of anomalous results, how to go about identifying them and what action we can take when we have found them.
Anomalous results are odd results - those which are not in keeping with the rest of the results or which do not follow any correlation you have spotted. If you have repeated your experiment several times, you will usually find fewer anomalous results than if you carry it out only once.
There can be many reasons for anomalous results. You may not have noticed that one of the control variables wasn't fully under control for that particular result. You may have added a little too much of something. You could even have written down the result incorrectly or mis-read it when transferring it from your notes to your report.
When commenting on anomalous results, always try to offer some sort of explanation e.g. "this result is much higher than those either side. This might have happened if I didn't control the temperature properly and it went higher during this part of the experiment".
There are two things that you can do with anomalous results. Firstly, if you have the time, you can repeat that part of the experiment, taking great care with quantities and making sure that the control variables are fully under control! Hopefully, a repeat of the experiment will give you a figure that fits with the pattern of the other results. The second thing that you can do is to simply not use them when drawing your conclusion. You may think that not using some of your results that don't fit the pattern that you have spotted is cheating. It isn't - anomalous results can make your conclusion unreliable especially if you are using numbers such as a numerical correlation of the independent and dependent variables. Professional scientists do this all of the time.
When writing up your experiment, it is really important to mention the anomalous results even if they don't appear in your final results table or graph/chart. It shows that you have worked carefully and are aware that experiments are not perfect. If you have been very careful and repeated the experiment several times, you may not have any anomalous results. In this case, simply mention in your evaluation that you can't see any anomalous results. That will tell the person marking your work that you are aware of the concept of anomalous results even if you didn't have any to comment on.
See how much you know about identifying anomalous results and what to do about them by playing this quiz on the subject.
The main purpose of the results is to point out trends or inconsistencies in your data but should not include explanations or opinions. The results section is a numerical, observational, and/or statistical summary of WHAT HAPPENED or WHAT YOU FOUND or SAW. Present your findings in a logical order (chronology is not a requirement). Present the data you have observed, not what you think you should have found. The observations are real regardless of what you think they should show! You may have to do some thinking to find out why the results came out differently that you expected.
Results can often be reported more effectively in the form of one or more tables or figures (plots or illustrations). These should have clear labels, titles, and captions and you must refer to them within the written portion of the results. Any tables or figures must be explained in the text as well, but do not repeat the numbers or entries in the tables or figures rather, summarize the trends, interesting observations, deviations from the ‘normal trends’, etc.. Refer to tables and figures in your text, but avoid sentences that include “Figure 1 shows. ” or “. as seen in Figure 1”.
The text should be kept as close as possible to the figure or table to which it refers without breaking paragraphs up into unnecessarily small paragraphs (remember, one sentence does not a paragraph make!). Alternatively, append tables first and figures second to the end of the assignment, as if you were submitting to a journal for publication. Likewise, do not create or insert sentences of no meaning just to conform to the definition of a paragraph. Instead, come up with logical ways of stringing ideas together. In some cases, the summary statement of a table or figure may only be one sentence and it will be impossible to place the text next to the table or figure. As well, a sound paragraph may include ideas from several tables or figures. In these cases, just place the tables or figures in order of citation within the paragraph. Do not present the same data in the text, a table, and a figure. Use only one of these options.
See the sections on Tables and Figures for more details on proper citing of tables and figures and other relevant information.