5.17

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

·         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