Photo courtesy of ACE CRC (photographer Simon Marsland)

Ice Investigation #1: If icebergs melt, will sea level rise?

Materials (per pair or team): deep dish pie or cake pan, toothpick, modelling clay, 2-3 ice cubes, water, clear plastic wrap

1. Give each team of students a pan and a lump of clay.
2. Mould the shape of a continent, pressing the edges flat against the pan.
3. Pour in water to partially cover the clay continent.
4. Put several ice cubes in the water to represent icebergs. (Note: The more ice you use, the easier it will be to see any changes in water level.)
5. Trace the water level into the clay with a toothpick or pencil.
6. Cover the pan with clear plastic wrap to prevent evaporation of the water.
7. Observe the marked water line as the ice melts. Does the water level rise? Why or why not?

Ice Investigation #2: If glaciers and icecaps melt, will sea level rise?

1. Use the same pans and continents from investigation #1.
2. Place 2-3 new ice cubes on top of the clay continent to represent glaciers or icecaps.
3. Observe the marked water line as the ice melts. Does the water level rise? Why or why not?

Water contracts as it cools until it reaches about 4°C. It then expands by up to 10% as it freezes, making it less dense than liquid water. (You can check this out by freezing a carefully measured volume of water in a plastic measuring cup, then checking the volume again.) Melting icebergs will not raise sea level because the volume contracts again when the ice melts. Melting icecaps and glaciers raise sea level, however, by adding more water to the ocean from the land.

Water also expands as it warms. Can warming the oceans as a result of global climate change affect sea level? Design an experiment to find out.