Friday 27 May 2011

Convection Currents in Liquids- Coloured ice cube experiment!


Coloured ice cube experiment

Click on the above link and watch the video. If you want you can try it at home. All you need is a transparent plastic cup, some warm water, food colouring and ice cube. After watching the video or trying it out yourself, try and answer these questions:
1.     When the ice cube started melting, what happened to the coloured melted water?
2.    Why do you think that the coloured meted water moved downwards?
You still cannot find a solution to this problem? Keep on reading.

Basically the process that is happening here in this experiment is called convection currents. Convection currents can be found both in liquids and gases. In this case, you are witnessing convection currents in liquids.

What is exactly happening to the ice cube? Due to the fact that the glass full of water is warmer than the ice cube, when the ice cube starts melting, cool water from it starts sinking to the bottom of the glass. Why does this happen? This happens because cool water particles vibrate less, take up less space, their volume decreases and density increases. Obviously something that is denser will sink to the bottom. That is what is happening to the melted ice cube! The green colouring is only representing the path of the melted water particles.

If you would like, you can record a video of this experiment and post it here and share your ideas with your classmates!!!!

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