The ice is melting

Activity 1

Earth observation satellites help us to see our world in a new way. They can
observe different features than those we can see when we look at our
planet from the ground. Studying these features can tell us about the health
of the Earth, our weather, our climate, and topics such as global warming, ocean
acidification, and much more.

Pupils will learn:

• Where ice can be found on Earth
• That the amount of ice on Earth is decreasing
• The difference between land ice and sea ice
• That melting sea ice does not affect sea levels
• That melting land ice does affect sea levels
• That it is colder on areas of ice (white) than on land and water (dark)

Pupils will improve:

• Their experimental skills
• Their ability to work in a group
• Their ability to plan an experiment
• Their ability to describe and explain physical effects that they see

Equipment

Information sources, such as the internet, an encyclopedia, or an atlasInternet connection.

Exercise

Pupils can use the information sources to research this topic and answer the questions on their activity sheets.

Discussion

Once pupils have completed their worksheets, they can discuss the answers as a class. You could ask for ideas about:

• The temperature at which water freezes to form ice (0°C).
• The different forms of frozen water (snow, hail, ice cubes, etc.).
• Where ice can be found on Earth (mostly at the North and South poles, Greenland, Siberia).
• We can find ice at the South pole (mainly land ice), at the North pole (both land ice and sea ice).
• The North Pole includes Greenland, which is land ice.
• Why the North pole has shrunk so much in recent years.
• The possible results of ice melting (e.g. sea levels rising).

 

Activity 2: Will sea levels  change?

Equipment (per group)

• 2 small plastic cups
• 2 small plastic plates
• 2 ice cubes
• Enough water to fill the two cups
• Modelling clay

Exercise

Pupils should first complete questions 1 and 2, where they predict what will happen as a result of ice melting. Then pupils split into groups of four in order to carry out the practical experiment.
Hand out the equipment and explain that the water represents the sea. Ask pupils to follow the instructions on their activity sheets.
Note that it may take quite a long time for the ice to melt. You can speed up the process by using lukewarm water, or putting the cups on a sunny windowsill.

Results

The water in cup 1 should stay at the same level, whereas the water in cup 2 should overflow.

Discussion

• Melting sea ice does not cause sea levels to rise, whereas melting land ice does.
• In ice form, the sea ice is already contributing its volume to the oceans. Thus, when it melts it does not increase the volume of the oceans.
• In ice form, land ice is not contributing to the volume of the oceans. When it melts, it flows into the ocean, increasing the overall volume.
• It is misleading to say that melting ice overall leads to rising sea levels. It is melting land ice that mostly leads to rising sea levels.
• Note that indirectly, melting sea ice can lead to rising sea levels, through changing properties such as the salinity, density, and current. But these effects are less extreme, and less measurable than the changing volume as a result of melting land ice.
• Ice is special because it is one of the few materials where its solid form is less dense than its liquid form, so it floats. This means that in ice form, the sea ice takes up more space than it does in water form.

 

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