Design an experiment
Summary
You are to construct a thought experiment on a topic specific to human biology connected to this
class and write a description of it. You’re experiment needs to address a specific, narrowly focused
question, and describe all the components of the experiment. You are not actually going to do it.
But it should be something that COULD be done. This assignment will be revised for a larger
written assignment later.
While your experiment can be based on previous research, your experiment should be original.
You should not need to do any outside research.
You should not worry too much on techniques (see below).
Because it is a thought experiment (and not actually done), ethical considerations can be relaxed (for
now). You can consider using “model systems” (see below).
Steps
For this part of the assignment, you will submit a proposal describing the design of a biological
experiment that is connected to a topic that has been (or will/may/could be) covered in class.
In your proposal, you will describe 1) what you are planning on testing; 2) why you plan on testing
it; 3) what you hope your experiment will show; 4) roughly how you are planning on testing it; 5)
what your dependent and independent variables are; 6) and all necessary controls.
Considerations
Things to keep in mind: your hypothesis and experiment should be extremely focused and clearly
defined; you should have adequate number of replication of the experiment as part of the
description; your sample size in your controls and treatment groups should be adequate; make sure
your dependent variable actually addresses your hypothesis; make sure you have enough controls to
eliminate other alternate explanations for possible results.
If you come up with an experiment that, after it were performed, one can’t draw any useful
conclusions from it because there were too many unanswered questions, or there were not enough
controls, or because it was a too broadly defined hypothesis or topic, then that experiment is not as
well crafted as it could be. Often the issue is trying to create an experiment that addresses too large a
question or has too large a scope. Recall that “big” discoveries are really based on anywhere from
scores to hundreds of smaller studies and experiments. With respect to controls, it is common for
there to be more than one, as a method to address potential variables.
Recommended steps:
• Brainstorm a list of topics covered in class. Use your lecture notes, resources posted on the
class site, or something you’ve read or always been curious about.
• Choose a few topics that most interests you – and picking something of interest to you is key
– and brainstorm some experiments that could be done.
• Avoid experiments that are subjective. For example, avoid any experiment that includes data
where you might ask the participants to describe how they feel or that has a survey attached.
Asking if someone “feels better” has too many variables. But you could collect data that
demonstrates “feeling better” like improved performance of a task.
• Of the one you like best, start to craft what the experiment might look like.
• Isolate all the conditions you need to control for. Come up with experimental controls to
avoid those.
• Think of how you can collect measurable data.
• Predict about what your data might look like, if you were to run the experiment. What would
it look like if the data support your hypothesis? What would the data look like if it doesn’t
support your hypothesis?
About data
Don’t focus on the technical aspects of how to measure something. For example, say you are
interested in seeing how a molecule affects the brain, with the hypothesis that the molecule reduces
some activity in a region of the brain. In your experiment, you can simply say you introduce a 1x
amount of the molecule, a 2x amount, a 3x or 4x amount, etc…. and you then measure activity in
the brain using imaging equipment. You can also say your molecule has a tracer (like an isotope, e.g.)
so you can follow where it accumulates. Notice you do not have to specify the molecule, the tracer,
or the way you are measuring the effect. You can then give the results (e.g. there was no change in
the region of the brain, but the molecule also failed to accumulate in that region, so it was either not
transported or was metabolized/degraded).
Model systems are a good way to do research. Examples include using cells where you might follow
a response cells have to a new medication. Or using other organisms and non-human animals – for
example, genetic studies often use everything from bacteria and yeast, to worms, fish, mice, etc…
Because this is a thought experiment, and because ethics is less a consideration, these are options to
think about but aren’t things you need to include.
DO NOT PERFORM THE EXPERIMENT!
Submission
Organize your submission using the following headings:
1. Title of Experiment
2. Brief summary of your experiment (see “Steps”) and conclude with your hypothesis statement
3. Description of your independent variable
4. Description of your dependent variable
5. Description of your control group(s)
6. A brief description of how the experiment will be performed, including the data being collected
and how it will be collected, and how the data support and don’t support your hypothesis.
Again, your written proposal does not require that you do any outside research or gather any
references, although you are welcome to do so. But be sure to properly site your source(s) following
APA guidelines.
The proposal should not be more than 350 words, excluding citations (if any).
Once again, do not perform this experiment!
Grading will be based on clarity of thought, practicality of the experiment, and how well thought out
it is.
In particular, 1) if it is an experiment, 2) how effectively it addresses the topic you select, 3) the
practicality of the experiment and how well thought out it is, 4) your data predictions and 5) the
clarity of the submission.
Evaluating the Impact of Intermittent Fasting on Insulin Sensitivity in Obese Mice
This experiment aims to investigate whether intermittent fasting (IF) improves insulin sensitivity in obese mice. We hypothesize that intermittent fasting will enhance insulin sensitivity, as measured by glucose tolerance tests (GTT) and insulin tolerance tests (ITT). This study seeks to explore the potential metabolic benefits of IF in the context of obesity.
### Hypothesis Statement
Intermittent fasting improves insulin sensitivity in obese mice.
### Description of Your Independent Variable
The independent variable in this experiment is the dietary regimen. We will have two groups: one group on a standard ad libitum (AL) diet (control) and another group on an intermittent fasting diet (IF).
### Description of Your Dependent Variable
The dependent variable is insulin sensitivity, which will be measured using glucose tolerance tests (GTT) and insulin tolerance tests (ITT). Insulin sensitivity can be inferred from the blood glucose levels measured at various time points after glucose or insulin administration.
### Description of Your Control Group(s)
The control group will consist of obese mice fed ad libitum (AL), meaning they have continuous access to food. This group will provide baseline data for insulin sensitivity without dietary intervention.
### Brief Description of How the Experiment Will Be Performed
1. **Induction of Obesity**: Place mice on a high-fat diet (HFD) for 12 weeks to induce obesity.
2. **Dietary Regimen**: After inducing obesity, randomly assign the mice to one of two groups:
– **Control (AL) Group**: Continue with ad libitum access to the high-fat diet.
– **Intermittent Fasting (IF) Group**: Implement a regimen of intermittent fasting, such as 16 hours of fasting followed by an 8-hour feeding window each day, with access to the same high-fat diet during feeding periods.
3. **Duration**: Continue the dietary regimens for 8 weeks.
4. **Data Collection**:
– At the end of the 8-week period, perform a glucose tolerance test (GTT) by administering a glucose solution after an overnight fast and measuring blood glucose levels at 0, 30, 60, 90, and 120 minutes.
– After a recovery period, perform an insulin tolerance test (ITT) by injecting insulin and measuring blood glucose levels at similar time points.
5. **Data Analysis**: Compare the results of the GTT and ITT between the AL and IF groups using statistical analysis (e.g., t-tests or ANOVA).
### How the Data Support and Don’t Support Your Hypothesis
– **Supporting Data**: If the IF group shows significantly lower blood glucose levels during the GTT and ITT compared to the AL group, this would support the hypothesis that intermittent fasting improves insulin sensitivity in obese mice.
– **Non-Supporting Data**: If there is no significant difference in blood glucose levels between the IF and AL groups during the GTT and ITT, this would suggest that intermittent fasting does not improve insulin sensitivity in this model of obesity.
