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Introduction
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Contents
1. What you can do
2. Water
3. Ecology
4. Amphibians
5. Environmental Issues
6. Keystone species
7. Get Wet!- Field Study Ideas
8. The Zoo Experience
9. Frogs & Friends
10. Case Studies
11. Resources
12. Glossary
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2.5. BIGGER THAN THE BOTH OF US
(Level: 2 : 5 :: Water Cycle)
Purpose: To observe the change in volume of water as it
freezes and to introduce the concept of hibernation in
amphibians.
What You Need: test tube :: waterproof marker :: beaker
:: crushed ice :: salt
What You Do:
- Fill the test tube half full with cold water and mark the
water level with the marker.
- Add crushed ice to the beaker with 1/4 teaspoon of salt
sprinkled on top.
- Insert the test tube in the middle of the beaker of ice,
ensuring it remains upright.
- As the water in the test tube cools, mark the changes in the
water level. Observe closely when the water freezes and mark that
level.
Questions:
- What are the 2 changes that occur in the water as it turns to
ice?
- Why does the water level drop before it freezes?
- The wood frog is the only North American amphibian to live
north of the Arctic circle. Amazingly, they can become living ice
cubes during hibernation. They produce a sugary antifreeze which
prevents their cells from freezing, although the remaining body
fluids freeze. A wood frog may freeze up to 50% of its
intra-cellular body water because they overwinter well above the
frost line. What reproductive advantage is there to hibernating
above the frost line?
Click here to see the answers to these questions.
Click here to go back to the list
of activities for this unit.
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