Teacher preparation:

Overarching learning goal: In this activity students investigate what happens when rising temperatures cause ice on land and in the sea to melt. Students will understand the difference between sea ice and land ice and will recognise that melting land ice will affect sea levels, but that melting sea ice won't cause as much of a rise in sea levels.

Teacher content information: Rising levels of greenhouse gases being trapped our atmosphere are causing our atmosphere to warm up (global warming). One of the results of this warming is melting ice at our poles. While this melting ice will dramatically affect the poles it will also affect sea levels. However, not all ice will have the same affect: land ice flowing into the sea will cause the total volume of water in the ocean to rise, while ice already in the sea will have a much lower effect on sea levels.

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This activity can be conducted as a class wide experiment, or students can work in groups to conduct this experiment independently.

Student and classroom organisation:

Step 1.

Begin this activity by asking students to describe the difference between sea ice and ice on land (e.g. sea is ice that is found in the sea, such as ice bergs and the ice in the Arctic. Land ice is ice that is found on land, such as in the Antarctic.)

Explain to students that one of the reasons that people are worried about temperatures rising around the globe is that rising temperatures could cause the ice at our poles (the Arctic and the Antarctic) might melt. Melting ice is not a bad thing in your glass of water, but when all the ice in on the land melts and runs into the sea it means that the seas get very, very full and start to overflow.

Where does the sea go when it overflows? Not into more sea, but onto the land; it causes the sea level to rise? But what about ice bergs; what happens when they melt? Do they also cause the water to rise up over the land?

In this activity, your students will be conducting two similar experiments, one to see what happens when ice on the land melts, and another to see what happens when sea ice melts.

Step 2.

Ask students to make some predictions about what they think will happen to sea levels when a) land ice melts and b) when sea ice melts. Ask students to record their results on the Student Worksheet.

Step 3.

Conduct your experiment

For this science experiment you will need:

Ice cubes
A waterproof tray
Sticky tape
Scissors
Water
Black marker
Ruler long enough to fit most of the width of the tray
Plastic sheet as land
Gravel to decorate land (optional)

Experiment steps:

1. In your tray, fix the plastic sheet to one end of the tray and let it rest on the bottom of the tray at the other end to create a slope. This plastic sheet is your land. (You can also decorate your ‘land’ with gravel to make it a bit more real.)

2. One quarter of the way down your slope fix a ruler across the tray to create a bar behind which you can rest your ice. You can fix the ruler with sticky tape – it will need to be fairly firm as it will need to stay there until the ice melts. You may need to leave a little gap below the ruler to let the melting ice through.

3. Pour a little bit of water into the bottom of your tray to represent the sea and using the marker pen draw a line indicating where the sea level is before the ice melts. You can also make a mark on the land showing where the water line is.

4. Add ice the land to represent snow, ice and glaciers. Allow it to melt and record the rise in sea levels.

5. Repeat the experiment, this time putting the ice into the sea to represent icebergs and sea ice. Again allow it to melt and then measure the amount the sea has risen.

Reflection/Assessment

Discussion - Following the completion of the experiment, ask your students the following questions (these questions can also be answered by students on the Student Worksheet):

What happened to the sea level when the sea ice melted? Did it go up, down or stay level?
What happened to the sea level when the land ice melted? Did it go up, down or stay level?
Can you imagine what would happen to the sea if all the ice in the Arctic melted?
What would happen if all the ice in the Antarctic melted?

Present results - Ask students to work in groups to create a simple poster or infographic explaining the results of this experiment. Students should include facts, stats, experiment results, and images (there are many images of Antarctica and the Arctic in the Cool Australia Arctic and Antarctica Toolbox ) or create their own.

Extension activity

Ask students to design their own experiments to show the differences between what happens when floating sea ice melts compared to ice on the land. How can they show the differences in these two circumstances?

Earth Hour - The Ice is Melting!

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