Cut the bottom off of a plastic bottle. If this is a project for kids, leave this part to an adult.
Slip a sock over the cut end of the bottle. If you like, you can secure it with a rubber band or ponytail holder. Otherwise, a small sock fits just fine or you can hold the sock over the bottle manually.
Squirt dishwashing liquid into a bowl or plate. Mix in a little water to thin it out a bit.
Dip the sock end of the bottle into the dishwashing solution.
Blow through the mouth of the bottle to make a bubble snake!