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Melting The Ice Caps

Don’t float away as the water rises

Australian Curriculum links

  • Science > Earth and Space Sciences > Year 4 > ACSSU075
  • Science > Earth and Space Sciences > Year 6 > ACSSU096
  • Science > Earth and Space Sciences > Year 7 > ACSSU116
  • Science > Earth and Space Sciences  > Year 10 > ACSSU189
  • Science > Nature and Development of Science > Year 7 > ACSHE223

You’ll need

  • Two large, clear containers
  • Two small containers (identical in size)
  • Plasticine
  • Water
  • Marker pen
  • Knife

Try this

  1. Fill the two small containers with water. Place them in the freezer to create two ice blocks.
  2. In one large container create a large mound of plasticine with a flat top to hold an ice block – this represents the Antarctic land mass. Pour water into the container leaving the top of the plasticine above the water.
  3. Fill the second large container with roughly the same level of water. This will be the Arctic Sea.
  4. Put an ice block on the plasticine mound in the ‘Antarctic’ container and one in the water of the ‘Arctic’ container at the same time. Mark the water level on the side of each container and wait for the ice to melt.
  5. Watch to see what happens to the water level as this ice melts and enters the ocean.

What’s happening?

The water level in the ‘Arctic’ container does not rise when the floating block of ice melts. This is because the water in the bowl is already supporting the volume of water when it is frozen as ice. However, the water level in the ‘Antarctic’ container does rise as the ice melts. This is because the ice is supported on ‘land’ (the plasticine) and the bowl is not supporting the volume of water frozen as ice.

Global warming is melting polar sea ice, polar glaciers and alpine glaciers. The effect of this ice melting on sea levels will be different in different places, depending on where the melting ice was stored originally – on land or in the water.

The main cause of sea level change is due to the amount of water in the ocean increasing or decreasing. This occurs when ocean water is exchanged with water stored on land. When ice sitting on land melts, water runs off into the oceans increasing the sea level. Melting of ice that is floating on the ocean will not contribute to sea level change. According to measurements from satellites, sea levels rose 3.1 mm per year from 1993 to 2003. Arctic sea ice has shrunk 3 to 5% since the 1950s. In Antarctica and Greenland, large ice sheets are showing signs of global warming related change.