This toothpick experiment is a really fun way to explore surface tension with kids. Just floating the toothpicks on the water is quite a discovery. What’s going on? Water molecules tend to want to hold onto each other. Think about how water joins together to form little beads when you drip it onto a smooth surface like a plate or wax paper. This is called surface tension. The water molecules in your dish are holding onto each other so tightly that the toothpicks are able to float on top.
Surface Tension Water Experiment - Water Drops On A Penny