Teacher preparation:

Overarching learning goal: In this activity students explore states of matters and 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: We need greenhouse gases in our atmosphere to keep the Earth at a temperature suitable to live. However, due to human activity increased levels of greenhouse gases are being trapped in our atmosphere, causing it to warm up (global warming). This is causing our climate to change and one of the impacts of this 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.

Cool Australia Presents Climate Change (https://vimeo.com/84835327)

About Earth Hour: Earth Hour is a WWF-Australia initiative, and is the world’s largest community-driven climate change campaign. At the centre of Earth Hour is switching off lights to show a commitment to taking action. Thousands of teachers use Earth Hour’s education program to enrich their curriculum and provide pathways for young people to create change in their world.

Download the Earth Hour starter kit for your school: Earth Hour for Schools

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. See, Think, Wonder

Students complete the See, Think, Wonder visual thinking tool on the Student Worksheet. It encourages students to make careful observations and thoughtful interpretations. It helps stimulate curiosity and sets the stage for inquiry.

Step 2.

Ask students to describe the difference between solids, liquids and gases. Discuss 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 3.

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 4. 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 - Melting Ice Experiment

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