Ice that calves into the ocean becoming a floating ice berg has the same effect on sea level as ice that melts and flows as liquid water into the ocean. You can demonstrate this yourself by using a glass bowl, some water, and several ice cubes.

First, fill the bowl with water, leaving enough space at the top to allow ice cubes to be added without overflowing, but deep enough so that the ice cubes will float.

Mark the level of the water surface on the bowl.

Add the ice cubes and mark the new higher level of the water representing sea level rise.

To determine the lasting effects, allow the ice cubes to melt and notice what happens to the surface level. Do you think it will be the same after melting as it was when the ice cubes were floating?

Extending the Science
Calculate your own estimates of sea level rise.

There are two major ice caps in the world that would have a global effect on sea level if they were to melt: the Antarctic ice cap and the Greenland ice sheet. You can make your own estimates of how much sea level would increase if the ice caps were to melt. Here's what you'll need to know:

• Look up in an encyclopedia or almanac the total ocean area of the earth. This is the area over which the added water from the ice caps must be averaged to obtain sea level rise.
• Convert the ice volume of the ice caps to the volume of water it represents. The volume of ice on Antarctica is approximately 7,033,274 mi³ (29,315,965 km³) and on Greenland it is 624,766 mi³ (2,604,142 km³). Ice is about 90% as dense as water, due to the gasses and other particles trapped within it; so the conversion rate is 0.9 to obtain the water volume of ice.

Estimates of sea level rise are made by dividing the water volume of an ice sheet by the total surface area of the oceans in which they will melt. How much will sea level rise if the Greenland ice sheet were to melt? And if the Antarctic ice cap were to melt?

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