Nazia Fathima and Gauthami Gopalakrishna the co-founders of ‘Decode X and Why’ believe in “Curiosity Enables Creativity and Awareness – CECA.” With this vision, ‘Decode X and Why’ has
worked with over 5000 children in Science, Robotics, Aeromodelling, and Communication.
In this article, Nazia and Gauthami describe some science activities that you can do at home with simple materials.
Pepper DanceMaterials required:
1. Take a plate and fill half its volume with water.
2. Sprinkle some pepper powder on it.
3. Dip the tip of a ear bud in the liquid dish wash.
4. Gently hold the tip of the ear bud onto the surface of the water and observe the pepper running away from the bud.
Water, like everything else in the world, is made up of atoms and molecules. The molecules on the surface of water are attracted to each other by a force which creates a film of molecules. This layer is responsible for the tear drop shape of a rain drop. It also enablessome insects such as the water strider, to float on water. When a substance such as soap is introduced to this layer, the force immediately breaks pushing the water molecules apart. This is why you can see pepper moving away – this is actually the molecules of water moving away from the soap. This phenomenon is called surface tension.
What is the real life application of Surface Tension?
Soaps are called Surfactants because they are known to break the surface tension of water easily. This principle is used in washing clothes to remove stains and in washing vessels to remove oil residue. Soap breaks the surface tension of water helping the oil and dirt to come off surfaces. This is also the reason for using soap to wash the oil off your hands, after you eat something oily.