5.17

5.17 starter

02 November 2011

20:01

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Why do the eggs get sucked into the bottles?!

Explanation
· The burning paper in the bottle heats the air in the bottle
· When the egg gets placed on top, the oxygen supply in the bottle is rapidly depleted and the paper goes out
· The bottle is sealed by the egg and now has a constant volume of gas inside
· The hot gas in the bottle now starts to cool which reduces the pressure inside the bottle
· The pressure outside the bottle remains unchanged and so there is now an unbalanced force on the egg which accelerates the egg into the bottle

5.17

28 October 2011

11:11
· 5.17 describe the qualitative relationship between pressure and Kelvin temperature for a gas in a sealed container

Instructions
· Launch the application on this website: http://phet.colorado.edu/en/simulation/gas-properties

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· Put 5 pumps of gas in
· Set volume as the Constant Parameter
· Heat to 1000K
· Watch what happens to the Pressure

Conclusion
· If you increase the temperature, you increase the pressure

5.17 Demo

02 November 2011

19:56

Cloud formation
· Place a little water in the bottom of a 1½ litre plastic bottle
· Squeeze a few times
· Introduce a small amount of smoke
· Squeeze and release several times
· When you squeeze, the cloud disappears; when you release, the cloud reforms

Explanation
· When the pressure increases the temperature increases and vica versa
· The "cloud" is water droplets - liquid water
· When you squeeze the bottle the temperature increases and the droplets turn into water vapour
· The smoke particles are nucleating sites on which the water can condense