What substances are less dense than water?
Ice Air is less dense than water, so water sinks below air. A rock is more dense
than water, so it sinks in water and air. And helium, which is less dense
than air, rises in air and in water.
Most commonly available substances that are less dense than water is oil, alcohol and plastic. In fact, a number of organic solvents such as acetone, methanol and methylene chloride are also less dense than water. In addition, a number of different kinds of polymer are "lighter" than water, too. Hmm... potassium and sodium? :D
Solid water, ice, is less dense than its liquid state. This is essential for aquatic life. Since ice is less dense than liquid water, it floats to the top of of the water. This insulates the water beneath the ice, allowing the water beneath the ice to remain liquid. For other substances, the solid state is more dense than the liquid state.
Yes, there are many. For example, anything that floats on water is less dense than liquid water. A number of solids are less dense than liquids. The most common example is ice. Ice (frozen water) is less dense than its liquid counterpart for some very specific reasons. Many other solids are less dense than liquids, as well. Using water as the liquid, you'll find that cork, wood (most kinds) and styrofoam will all float on…
For most substances, the solid phase is more dense than the liquid and gas phases. The liquid phase is less dense than the solid phase but more dense than the gas phase, and the gas phase is less dense than either the solid or liquid phases. Water is an exception. Its solid phase (ice) is less dense than the liquid phase.