What you need :

- A water-filled container

- 2 Bottles

- Vinegar

- Chalks

- Pierced top with a tube sticked on it

Method :

- Fill the container with water and fill a bottle of water in the container and turn it over

- In another bottle put spirit vinegar and chalks to make CO2

- Wait a little bit to fill the container of CO2

- Transfer the CO2 in the bottle with a pierced top and a tube until there is no water in the bottle

- Cork the CO2 bottle without coming it out from the water

- Cork the CO2-filled bottle in and out of the water

- Mark the contents of the 2 bottle (one with air and one with CO2)

- Place thermometers in each bottle

- Put in a heat source