The classical way of demonstrating surface tension.

When talking about surface tension, the classical thing to do is to talk about the shape of drops of water.

Water drop on a coin.

As seen before in this post, the drops of water act as lenses.

It is pretty amazing how much water you can pile on a single coin!

If you can’t see it from the photos, here’s a video. But rather than watching the video, you should try it yourself. It’s fun!