Why Don’t Whales Have Legs? Lab Activity
You will need to complete the following on a separate, typed sheet of paper.
 Background
 Materials
 Purpose
 Procedure
 Variables
 Data
 Hypothesis
 Conclusion
Background: Using your prior knowledge about whales and the information discussed in class, describe some background
information about the evolutionary information available about whales before forming a hypothesis and procedure. This
description should be in paragraph format in your report.
Purpose: Discover a reason as to why whales do not have legs, despite having the vestigial structures of hind limbs. Write
this sentence as the purpose in your report.
Variables: Name the independent, dependent, and controlled variables of your experiment. In your report, simply list each.
Remember there is only one independent and dependent variable, but there can (and should) be several controls.
Hypothesis: State your proposed explanation of why whales don’t have legs. Be sure to refer to this hypothesis using “If…,
then…, because….” format in your report.
Materials:
 One large container or sink that holds water
 One latex or plastic glove
 Two small plastic bags
 One rubber band
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One Styrofoam cup
Hot water
Cold water
One thermometer
You may not need to use all materials – Be sure to only list materials you actually used in your report!
Procedure: Use the materials and prior knowledge to develop a hypothesis and to design an experiment that would support
why whales no longer have legs. Then, formulate a procedure that would test the hypothesis, using the materials listed
above. Be sure to identify the variables and control. Also, consider: What is the data going to look like?
(Hints: You need to create a whale, so think about the environment they live in. Also, you many need to look up the word
homeostasis.) For your report, number each step of your procedure, giving clear instructions so that anyone could replicate
your lab.
Data: You should be able to collect measurable evidence to support your conclusion and present it in a clear manner here.
Be sure to create a data table and graph with properly labeled title and axis in your report.
Conclusion: Answer the question “Why don’t whales have legs?” using the data and addressing your hypothesis. For full
credit, be sure to include possible experimental errors and recommendations for further experimentation in your report as
well.
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