Experiment kids – Make float a piece of metal

experiment kids water

In this little experiment kids, we will discuss the surface tension of water. We will illustrate this by floating a piece of metal on water.
What is surface tension?
It is a force that is exerted on two elements of a different composition. For this experiment, these will be water and air.

Equipment of this experiment kids:

  • A glass of water
  • A needle
  • A sheet of cigarette paper
  • Washing-up liquid

Instructions of this experiment kids:

Fill the glass with water and gently lay a sheet of cigarette paper on the surface. Immediately place the needle on the sheet. For the moment, the two elements float.
Allow the paper to soak up the water and slowly sink. The needle does not sink, but remains on the surface.
Add a drop of washing-up liquid to the water. The surface tension is broken. The needle sinks!!!

Explanation of this experiment kids:

The needle floats on water because of the surface tension. Imagine that the water in contact with the air is covered with a thin, very resistant skin. This skin is strong enough to support a small object. Thanks to this tension, water spiders can move across the surface of the water.

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