Bubbles and surface tension

The other weekend, we decided to learn about surface tension.  I took a plastic plate and filled it with water, then sprinkled pepper on the surface of the water.

Once everything was still, I added a few drops of dish washing liquid and watched the pepper speeding around the surface of the water as the soap changed the surface tension.

I wanted to make patterns, so I added some food colouring to the water.  The green colour just sank to the bottom.  It was boring, so to make it fun again, I took a straw and started blowing bubbles.  That was the best part.