When ice melts, all of the hydrogen bonds do not collapse at once. The cagelike framework disintegrates piecemeal, and even in liquid water at room temperature there are clusters of several hundred water molecules hydrogen-bonded together in ways similar to that of ice. As the temperature is raised, these icelike domains break up more and more, and the same quantity of water takes up less room. At the same time, the bulk solution is expanding as the temperature rises. These two effects are in competition. When ice first melts, the breaking up of the cage structure predominates, and water contracts. It continues to contract as the temperature increases from 0C to 4C, and more of the icelike structures are broken up. Not until the temperature rises above 4C does the normal thermal expansion become more important than the breakup of the hydrogen-bonded cages. Water has its minimum volume and maximum density at 4C, and only above this temperature does it begin to expand as it is heated, as does any other liquid.