Curly Fish Trick

School your friends with this curly fish experiment. Don't forget to tell them how it works when you're done.

What You'll Need:

  • Celluloid
  • Scissors
  • Bowl of water

Curly Fish
Curly Fish

How to Make Curly Fish:

Step 1: Cut a simple fish shape from a sheet of celluloid. Your fish should be about four inches long and one inch wide at the widest part of its body and one inch wide from tip to tip of its V-shaped tail.

Step 2: Drop the fish into a bowl of water.

Step 3: Tell a friend that your fish is so lifelike that if someone picks it up out of the water, it will curl up. When your friend picks up the fish from the water and puts it in his or her hand, probably nothing will happen. But if you rub your two hands together vigorously and then ask your friend to put the fish flat on your open hand, the fish will curl its head and tail together within a few seconds.

Why Did It Work?
The friction from rubbing your hands together created heat, and the heat was passed on to the fish. However, the plastic fish did not warm evenly. The bottom part touching your warm hand warmed faster and caused the plastic to expand, but the top, colder surface remained the same. This difference in the temperature of the top and bottom sides of the fish caused it to curl.

Keep reading and find out how to observe fish eggs in their outdoor habitat.

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