Changes of state

make ice cube out of strong ribena, pretend he is your pet - accidently drop him into clear bowl of warm water and act distraught as he melts - watch colour of water! Good starter for particles and change of state

One method I have used to demonstrate evaporation on a sunny and windy day is pick a pupil to be a pair of wet pants.. (or any other item of clothing) They hold straws or any other small items. The straws are droplets of water. Other pupils are wind molecules. Several wind molecules crowd around the pants and take one water drop, but as there's no wind only a few can reach. Then it starts to get windy and other wind molecules can pass by and take a water droplet away, thus drying the wet pants.

KS3 adviser in today had a cute demo - used a clear bag of coloured toy balls from Argus to show how a solid was, go them thinking about how good a model this was for a solid etc.

I also use the plastic playballs but I get the kids to tip them onto a bedsheet and stand in a large circle, shaking the sheet up and down- small amount of energy imputted (small shakes)= solids, larger shakes mean you are giving the particles more energy etc.etc. The balls get tossed completely out of the sheet when I call the word 'gas' - good to do on the playground.

I was trying to explain solids, liquids and gases in terms of atoms to a bunch of first years and they weren't quite getting it.

So, I used them to represent the atoms, first they stood in a bunch and swayed a little bit.

Then I pressed play on the CD player (Curtis Mayfield's "move on up" was the tune I used, but I'm sure any up tempo tune would work) and told them that the volume of the music represented the amount I was heating them up. Being young, they all started dancing withouth being prompted and I explained that they were no longer a solid but now a liquid - they were moving about more and were a bit further apart than at the beginning.
Then I turned the volume right up and told them that they now had loads of energy and should go off around the room and that they were now a gas.

Then I did it all backwards and they all got it.

I could even vaguely explain the principle of diffusion by using the fact that when they were a gas they were all over the room.

Since you can't use crude oil to demonstrate fractional distillation, and the substitute we used was rubbish, fractionally distil Dr Pepper or Cherry Coke. You even have a model for the petroleum gas fraction.

An idea to show how the state of matter is important:

Put a fingerprint on a microscope slide
Put small amount of superglue on piece of kitchen foil
Put kitchen foil into bottom of small beaker
Put slide into beaker & cover with clingfilm/foil
30 mins later you should see a perfect fingerprint as the fumes from the evaporation of the superglue sticks to the print.

Superglue:
as a liquid - so it can be squeezed
as a solid - holds items together
as a gas - used by forensics to visualise prints.