This activity will show you how the melting of different types of ice impacts sea level rise.

Activity steps

1. Place the two cans of food in the clear containers (ideally the height of the containers should be higher than the cans).
2. Into one container put a mixture of ice and water, until it comes up to about 1cm below the top of the can. This is the Arctic Ocean model. The ice in the water represents the sea ice.
3. In the other container pour water (again until it comes up to about 1cm below the top of the can). Then place the same amount of ice used or the Arctic on top of the can. This is the Greenland or Antarctica model, where there is an ice sheet on top of the land.
4. Label each container and mark a line at the water level. What will happen to the water (sea) level as the ice melts?
5. Leave the cans for a time (up to 2 hours). The melt rate will of course vary with the warmth of the room and the amount of ice used.
6. Mark the level of the water after all the ice has melted. What difference can you see between the two containers?

Activity materials

• 2 full cans of food
• 2 clear containers (ideally slightly wider and taller than the cans)
• Some ice
• Marker pen

Expected results and answers

Sea level rise is caused by two main factors: thermal expansion and melting ice. Thermal expansion refers to the fact that when the temperature of a liquid rises, so does its volume. You may also have seen news stories about how melting ice in the polar regions will affect sea level rise, but let's find our how not all ice is equal.

The ‘Arctic Ocean’ container should see little rise in the level of the water. Melting sea ice causes little impact on sea level, as this just represents the sea freezing and thawing without the addition of other water sources.

The ‘Greenland’ or ‘Antarctica’ container should see a greater rise in the level of the water, potentially ‘flooding’ over the top of the can. Melting ice on land can have a significant impact on sea level rise, with 99% of the freshwater on the planet stored in the Greenland and Antarctic ice sheets.

People living in coastal areas around the world, including the UK and USA, would be more susceptible to flooding if the ice on land (e.g. the Greenland and Antarctic ice sheets) melted but melting sea ice would have little impact. It is estimated that global sea levels would rise by an average of 66 metres if all the ice sheets were to melt.

A study published in the journal Science in 2012 estimates that 4 trillion tonnes of ice from the Greenland and Antarctic ice sheets has melted between 1992 and 2011. This has resulted in an 11mm rise in sea level, contributing about 40% of the total sea level rise during this period.