When it's cold outside, some animals hibernate.
Some hibernating animals don't move or eat for three months! How do
they stay warm?
Try this experiment and find out.
What you need:
- Two plastic bags
- A bowl of water and ice cubes
- A stopwatch
- Two large rubber bands
- A willing volunteer
- Put one hand inside one of the plastic bags.
- Ask your helpful volunteer to spread a thick layer of Vaseline
over your other hand.
- Slide the second plastic bag over the hand with the Vaseline
- Squeeze the air out of the bags.
- Put a rubber band over the top of each of the plastic bags to
stop them falling off. Make sure it's not too tight!
- Stick your hands in the bowl of ice water. Don't let any water
get inside the plastic bags.
- Time how long you can keep each hand in the water for. Make
sure you take each hand out when it starts to feel uncomfortable.
Don't hurt yourself!
Did one of your hands start to feel uncomfortable before the
Most people can keep the hand covered in Vaseline in the water
for longer than the other hand. Vaseline is an insulator. It keeps
the heat from your hand escaping into the water. The hand without
Vaseline doesn't have this extra protection and it loses heat
quickly to the water.
Animals grow a thick layer of fat before they hibernate. This
fat acts just like Vaseline. It is an insulator. Fat helps to keep
the animal's body heat inside the animal. It prevents the body heat
being lost to the surroundings.
Find out more about how animals
stay warm in winter.