Natural phenomena and simple experiments can be learned at any moment. There is no need to wait for science courses at school, and there is no need for a dedicated laboratory to practice it. Experimenting with tools and materials are simple, and leisure time at home can be used to gain insight and knowledge.
Tools and Materials of Simple Experiment – Soap Splits the Pepper Layer
Dab soap/liquid soap
Step of Simple Experiment – Soap Splits the Pepper Layer
1. Pour water into a bowl up to about three quarters of the way.
2. Sprinkle pepper powder evenly over the surface of the water in a bowl.
3. Immediately insert the tip of the index finger into the middle of the surface of the water that has been covered by pepper. Make sure your index finger is snugly in the middle of the surface of the water. Nothing happened right?
4. Pepper coating remains intact, does not budge. Likewise, even though the index finger has been lifted from the surface of the water, the pepper coating that covers the surface of the water does not show any significant changes.
5. Once removed, rub the index finger with dab soap. Place your index finger back into the water in the pepper-covered bowl.
6. What happened? The pepper layer split apart, as if avoiding a finger that had been smeared with liquid soap.
7. When the forefinger is lifted, the pepper layer that splits cannot be reunited.
Explain of Simple Experiment – Soap Splits the Pepper Layer
The splitting of the pepper layer by the index finger covered in liquid soap indicates the phenomenon of something changing the stability of the water surface. Water in a container always has surface tension. Surface tension is the force caused by an object acting on the surface of a liquid around the surface area of the liquid in contact with the object.
Surface tension in liquids is influenced by the cohesive force, or the attractive force between similar molecules, namely liquid molecules. This cohesive attraction makes the surface of the liquid appear to be covered by an elastic layer. The existence of this surface tension causes the liquid to be able to hold small objects on its surface, such as insects that perch on water, pepper powder that does not sink, cork that floats.
When a soap-covered index finger is submerged in water, the liquid soap molecules break the surface tension of the water so that the pepper coating that covers the surface of the water splits away from the soapy index finger.