How does surface tension work? Explain with this easy DIY chemistry experiment Â
Surface tension is one of the earliest foundational scientific principles taught. When it comes to explaining such scientific concepts to kids, what better way to do so than through practical experimentation? Not only does it help them understand a concept with much more clarity, but is also equally fun to do. This simple DIY experiment demonstrates surface tension using basic materials which can easily be found in the kitchen, and is a sure hit amongst kids. Read on to find out how you can perform this experiment at home.
What you will need
Gather all these basic materials and get your budding scientist ready to conduct this super easy experiment.
- Black pepper
- A plate
- Water
- Liquid soap
Step-by-step guide
This fun experiment packs in a great deal of learning, and can be conducted within 5 minutes. Help your kid follow these steps.
- Fill the plate with some water. Ensure that this is a thin layer of water, even less than an inch is sufficient.
- Sprinkle the pepper over the water. Remember, over here, add as much pepper as your child would like to and cover the entire water surface. (Ask your child to wear swimming goggles while doing so, and wash off all the pepper after the experiment for safety.)
- Ask your child to dip his finger in the liquid soap.
- Next, ask him to touch the pepper floating atop the water in the plate. Observe what happens.
What exactly is happening in this experiment?
This experiment clearly shows how surface tension works. It is the tendency of liquid surfaces which are initially at rest to shrink into the minimum surface area possible. It exists in liquids because the molecules like to stick to each other. In this specific experiment, the liquid soap, when it comes in contact with the pepper water, breaks the surface tension of the water. Here, the water has a high surface tension, and hence, its molecules get pulled towards each other and stick together firmly. However, when they come in contact with the liquid soap, the surface tension breaks. The molecule which are in close proximity to the finger that is dipped in the water get pulled away by the molecules which are farther away.