Ice melting at sea
1. Some land areas have ice on them all year round. Again children can check these using globes – but this could all change with global warming.
2. Hand out the ‘What happens when ice melts on land’ investigation sheet 17b to pupils. Each group is going to create a ‘mini’ land area (mountain) and see how sea (water) levels are affected if ice melts on land. This is a model on a small scale for what might happen if global warming causes the permanent ice on land to melt.
3. Children work in groups to conduct the experiment as set out on the activity sheet. Children should be encouraged to observe carefully as the ice melts and to note what happens to the water produced. All groups should find that the water (sea) level goes up. Note: This change will be much easier to observe if the initial quantity of water in the tub (sea) is quite small and the initial quantity of ice is quite large.
4. Children discuss their results as a class. Suitable questions include:
> What happened to the water level in the tub as the ice melted?
> Will ice melting on land change sea levels?
> How might this affect a country like Ireland?
> What if you lived near to the sea/coast?
5. At this point it would be important to enable pupils to see that they can make (small) changes to their own lives to reduce energy use and wastage, and hence that they can have an impact on reducing global warming.
Notes
• Ensure that children are aware that it is acceptable to have different points of view and different, but equally sensible sounding reasons – after all, scientists don’t always agree!
• If preferred, ice balloons can be used rather than ice cubes. These will give each group a larger ‘lump’ of ice to use.
To prepare an ice balloon, attach a round balloon to a tap and fill with cold water until it is about 5-10cm across. Tie off the balloon. Place water balloons in a tray and freeze in a large freezer. Pupils will need to cut the balloon ‘skin’ off the ball of ice for each investigation.