Water is unusual in that the solid form has a lower density than the liquid form.
Ice therefore will float on water. This turns out to a very important and unusual property. The overwhelming majority solids are denser than the liquid and therefore sink. For example if one melts solids such as butter or chocolate on the stove the solid will stay on the botttom of the pot. Ice skating for example works because when ice is under the pressure of the blade it turns to the liquid form because the liquid form is denser.