Why do polar bears have a thick layer of fat under their skin? Try this activity and find out.

What You Need

• 1 large bowl
• 1 tray of ice cubes
• 4 medium-size, resealable plastic bags
• 2 cups of solid vegetable shortening
• Cold water

What You Do

1. Fill Bowl With Water and Ice
   Fill the bowl with cold water and ice.
2. Put Shortening in Plastic Bag
   Tell your child that the shortening is a kind of fat. Put this fat in one plastic bag.
3. Cover Hands With Plastic Bags
   Cover one hand with another plastic bag. Then place the covered hand inside the plastic bag with the fat and seal. Move the fat around until it covers the hand. Cover the other hand with the remaining two plastic bags (without fat) and seal.
4. Put Hands in Water
   Put both hands in the bowl of ice water.
5. Talk About What Happened
   Ask your child:
   • Which hand stayed warmer? (The hand covered in fat)
   • Why? (The fat helped keep the cold out.)
   • Polar bears have a layer of fat under their skin that is 4 inches thick. How does this fat help them? (It helps keep the cold out.)
   • What other features help polar bears to stay warm? (Woolly undercoat traps body heat; small ears help prevent heat loss; fur between paw pads keep feet warm.)