On hot days, we all look for ways to cool off. These scientific experiments to do with children are perfect to enjoy outdoors where the test laboratory will be a plastic paddling pool or similar . Science and fun go hand in hand.
The magic of buoyancy
How is it possible that ships, as heavy as they are, float on the water and not sink? With this experiment we will discover how buoyancy works, that is, the ability of a body to float. Objects remain on the surface due to the buoyant force. Let’s see what we will need:
A large container of water (a kiddie pool would be ideal)
Paper napkins
Clay
Small objects (which must all have the same weight; a handful of coins, for example).
Once we have all the materials, we will take some plasticine and make a ball with it, approximately the size of a golf ball. We will then place it in the water. Does the plasticine ball float? We will collect the ball and dry it with a paper napkin. Now, we will try to give our plasticine a boat shape and then place it back in the water. Voilà! The plasticine boat floats thanks to the “magic” of buoyancy. The next thing we will do is place coins in our new boat, observing its ability to stay on the surface.
You can experiment with different sizes and shapes using different amounts of modeling clay. How many coins will it take before it sinks underwater? Why do some shapes (ball or boat shape) float better than others?
Coins that disappear
Thanks to this experiment with water we will teach you the phenomenon of refraction. We will need:
1 coin
1 crystal glass
Water
We will take the empty glass and place a coin in the bottom. We will fill the glass with water, noting that, for now, the coin is still reflected in the bottom of the glass. This is because at this location on the coin, the reflected light reaches our eyes. However, if we place the coin under the empty glass and then fill it with water. What happen? The coin becomes invisible! In this case, when looking at the glass from another side, the refraction makes us believe that the coin has disappeared.
