The first experiment
Needle floating on the surface of the water
You can float a needle on the surface of the water?
The following experiment that enables you to check it out.
1. Pour the water in the cup.
2. Put the needle on tissue paper and placed gently on the surface of the water. What do you notice?
3. Apply a drop of cleaning liquid in the cup. What do you notice?
When you put the cloth on the surface of paper towel and dive into the water longer needle floating on the surface of the water, and the password that the surface of the water act as a membrane stretched over it a needle, called this property of liquids tighten surface.
But when you put a drop of cleaning liquid in the water, the intensity of the surface will be less sinks the needle.