Why Don't Whales Have Legs: Introduce Your Class to Inquiry
By Kate Silber
Highland Park High School
Highland Park, IL
Inquiry will be a new approach for both you and your students. The following activity will give your students an idea of how a guided-inquiry activity will differ from the "cookbook" labs they are used to. It is quite likely they will be confused by the process and will feel uneasy that there is no right answer to devising a project that answers the question at hand.
Teacher Tip: This activity is best done during an evolution unit. Feel free to share basic information with your students or allow them to explore topics outside the classroom like whale body composition and ocean temperatures. Students should be able to show that a whale without legs (baggie) retains more heat than a whale with legs (glove). Since the bag and glove are made of different materials, some students may tie the fingers of the gloves to show a whale without legs. It works best if the ocean (bucket) water is very cold (between 2-10° C) and the whale (glove/baggie) is about 37° Celsius.
In this lab you will propose a reasonable hypothesis as to why whales do not have legs. You will then design and carry out an experiment to effectively test your hypothesis.
You may work in pairs ONLY! You will turn in 1 full lab report for each pair. You many not talk to other groups or ask the teacher any questions. You have 1 double period to design and carry out your experiment. If your data does not make sense, you should adjust your procedure. Please follow all guidelines to making a good lab experiment, including controlling variables and multiple trials.
- Container to Hold Water (bucket)
- 2 Latex Gloves
- 2 Small Resealable Plastic Bags
- 2 Thermometers (Celsius scale)
- Hot Water (from the sink)
- Cold Water (from the sink)
Please write out every step so your grandma could repeat your lab!
Be sure this is in a neat, understandable data table. You will turn in the original data.
- Did your results support your hypothesis? Why or why not?
- If you could re-design your experiment (with additional materials), what would you do differently?
- Using terms we have talked about in class, explain the evolution of whales from terrestrial mammals. Yes, you will have to think back to September.
- Why do whales not have legs?
For the Teacher
To Be Turned In
- Formal lab report with original data table (not typed)
- A poster presentation of their findings so students can look at each other’s work and defend their results
Very Cool Extra
Check out this video of whale DNA. Start at 49mins.
It will be your job as the teacher to ask leading questions to get the students thinking about the question before them. Some samples include:
- How does the body shape of the whale differ from that of an animal with legs?
- What is different about the habitats of animals with and without legs?
- Is it necessary for whales to have legs?
- What types of variables will you be able to adjust in your experimental design?
- How will knowledge about changes in those variables help you conclude why whales do not have legs?
The more that you can pull from the knowledge that your students already have, the more they will learn as they start to hypothesize answers to questions that they do not have the answers to. Working through the process with a fun activity like "Why Don’t Whales Have Legs" can help decrease the stress when they get to a topic such as photosynthesis.