Build a Bathtub Toy Raft Powered by Surface Tension

Introduction

Have you ever wondered why a water strider can walk on water? Or how detergent can clean your dishes? If you look around you carefully, you can find dozens of similarly interesting phenomena that are all linked to the surface tension of water. In this science activity, you will make a little toy raft that is actually powered by surface tension, and use your vessel to investigate how surface tension works!

Credits

Materials

• A small, flat piece of Styrofoam, at least about three inches by three inches. For example, this could be part of a take-out container or a meat packaging tray.
• A toothpick
• Kitchen sponge. Use either a fresh sponge or rinse the sponge thoroughly with water to make sure it does not have any soap in it.
• Liquid dish soap or liquid laundry detergent
• Water
• Large basin, sink, or bathtub
• Scissors
• Utility knife or X-ACTO knife
• Optional: Medicine dropper and ruler