You may be thinking of icebergs.
IceFlows.
Glacier tongues that break off the Antarctic ice sheet are called icebergs once they disconnect from the sheet.
Ice Flows or Ice sheets (For 5th grade Jump Start game it's iceflows)
These are called icebergs.
Floating Icebergs
The winds that blow off the ice sheets of Antarctica and Greenland are known as katabatic winds. These downslope winds are dense and cold, originating from the high ice sheets and flowing towards lower elevations due to gravity. Katabatic winds can have significant impacts on local weather and climate.
The ice sheet that covers 98% of the Antarctic continent does calve off icebergs, but the continent itself does not 'break off'.
In order to remove chewing gum, start by freezing the sheets. THis can be done easily by putting them outside if it is winter where you are. The gum will then break off easily. Once you break the gum off, thaw the sheets, pretreat the remaining stain, and wash them as you normally would.
Chunks of continental glaciers that break off from the edges of the ice sheets produce icebergs. These icebergs can drift in the ocean and pose a hazard to navigation.
Floating Icebergs
Icebergs that break off the Antarctic ice sheet are composed of fresh water.
Generally it's made of graphite. Graphite is a substance made of carbon. The carbon atoms are bonded together in a particular way that allows "sheets" of graphite to break off easily. When you write something, some of these sheets break off and end up on your paper.