Fill the glass with water to the rim, and then add more drops slowly using an eyedropper. You will see that the water won’t poor out of the glass thanks to a soft skin that forms over the water, which in science is referred to as surface tension. That’s how insects can walk on water. To demonstrate this you can slowly put a paper clip on the surface of the water and it will float. This part is very tricky and you might sink a few paper clips before getting it right. It is very important to be as gentle as possible otherwise the layer will break and the paper clip will fall down to the bottom of the glass. You can hold the paper clip with a pair of tweezers or use the rim of the glass for initial support.