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In the film, pupils from Rurubao School in Kirabati are carrying out an experiment to show how warming water contributes to rising sea levels. Have a go at carrying out the same experiment, heating up water in a bottle and observing the level rise as the temperature increases.

This has been adapted from a number of resources by the Royal Society of Chemistry. You will be using warm water, so be careful. You may need an adult to help you with this. 


  • Fill a bottle with cold water and add food colouring to make it easier to see the water
  • Put the straw in the bottle and secure it in place with blu tac or plasticine. Place the bottle inside the larger container
  • Mark the current position of the water on the straw using the marker pen
  • Add warm water to the larger container
  • Observe the level of water in the straw over five minutes and watch what happens.