Day 1205 | Soap-Powered Fish
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Robbe was begging for a science experiment the other day (do other kids do that?!?) so we pulled out our trusty Big Book of Science Things to Make and Do and managed to find the perfect sciency-activity to squeeze in before dinner: the soap-powered fish.
Soap-Powered Fish
What you'll need
- thin cardboard
- wax crayons
- a large clean dish (we used a cookie sheet with a decent rim)
- a toothpick or kabob skewer
- liquid soap (we used Dawn)
Directions
- Draw a fish's body on the cardboard. Add a v-shaped tail then cut out the fish. Use wax crayons to decorate the fish.
- Fill a large dish with water. Then, use a toothpick or skewer to dab a blob of liquid soap around the "v" part of the fish's tail.
- Hold the fish flat above the water, with its tail near the edge of the dish. Carefully lay the fish on the water, then watch to see what it does.
**If you want to do this project more than once, thoroughly rinse and dry your dish each time or your fish won't move.**
Why does the fish move?
The skin on the surface of the water is held together by a force called surface tension. When the soap on the fish's tail touches the water, it forms a soapy film behind the fish that pushes the skin on the water away. This propels the fish forward in the water.
Science is cool. And this experience had all the elements of a perfect project: quick + household supplies + no-mess + the excitement factor. It's just sad the fish don't really survive the swim. Prepare your little ones accordingly.
