Runaway pepper experiment
- Pour 500 ml of water into the tray.
- Sprinkle a pinch of water on the water. Pepper floats on the surface.
- If you touch the surface with your finger, will something happen to it? Apart from the fact that pepper stays on your finger, nothing changes.
- Now touch the bubble base first with your finger and then the water surface. What happened? The pepper seems to have magically jumped away from the finger. Why did this happen?
When you put a clean finger in the water with pepper, nothing spectacular will happen, but when you dip your finger in the bubble base before, the pepper will spread over the surface of the water. This is because bubble liquid is a substance with unusual properties – a single molecule of such a substance consists of a hydrophobic (water repelling) part and a hydrophilic (attracted by water) part.
This structure of the particle means that when it is laid on the water surface, instead of lying on its side, it stands vertically, just like a float on the water. When we add a surfactant to the surface of the water, millions of particles standing in this way are arranged next to each other, forming a layer that spreads across the water. This layer also sticks to pieces of pepper and kidnaps them. In the same way as detergent pepper, water and detergent removes grease and dirt from the skin. Science allows us to take better care of hygiene 🙂