Who is the cartesian diver

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Information about your use of this website will be shared with Google and other third parties. Read our privacy policy. Use this famous experiment to illustrate the changes in density of gases and liquids when compressed. Descartes was a French scientist and philosopher. The Cartesian diver can be used to illustrate the behaviour of gases and liquids when compressed. In this experiment a Cartesian diver is constructed and some of the properties observed.

This practical is part of our Classic chemistry experiments collection. This activity could be used to stimulate discussion around what the children are observing in the demonstration. It also could provide a stimulus for research into the phenomena they have seen or into the scientist that discovered it.

This activity deals with some concepts around the density of gases and liquids which may be difficult for some children to understand. Get hands on with H 2 O, changing states of matter and the water cycle. These experiments and investigations involve water in the context of space. Connect your curriculum teaching on chemical changes to engaging sustainability contexts.

This topic web suggests classroom activities linked to plastic degradation and clean cooking. Connect your curriculum teaching on electricity to engaging sustainability contexts. Since objects only sink when they are more dense than the medium they are in, a Cartesian Diver is an object that can easily be made more dense by applying pressure.

In this case, the packets of mustard and soy sauce are only very slightly less dense than the liquid in the bottle - they barely float - and, due to the way they are made, each has a small bubble inside it.

When the bottle is squeezed, the air bubble is compressed, and the packs become more dense, eventually exceeding the density of the liquid around them so that they sink. Remember, density is a measurement of mass per volume, or "how much stuff in how much space," so making the packs smaller by compressing the air bubble in them means that they are more dense, given that this means they have the same amount of matter in a smaller space.

When you let go of the bottle, the air bubbles in the packs re-expand, and the packs float again. The reason the soy sauce packet sinks first is that it is closer to the density of the liquid in the bottle and thus has to be compressed less before it sinks.

Fill a bowl with water and see if your packets naturally float or sink. If a packet floats well, wrap a bit of fine copper wire around it to make it just barely float.

The eye-dropper sinks! Stop squeezing and the dropper rises once more. Today we'll explain why this works. When you squeeze the sides of the bottle, you are increasing the pressure on the liquid inside. That increase in pressure is transmitted to every part of the liquid.

That means you are also increasing pressure on the eye dropper itself. Squeeze hard enough and you will push some more water up inside the dropper.

The air inside the dropper squeezes tighter as more water is forced in. Now, water is much denser than air.