So a helium balloon floats! Water has a higher density than air. The particles in a solid are tightly packed, so a lot of particles fit into a given space. This means solids have relatively high ...

The element is also employed in medical equipment such as lung ventilators, where a mix of oxygen and helium aids patients suffering from respiratory issues by reducing the density of the gas mixture.

The Micromeritics helium gas displacement pycnometer allows the non-destructive measurement of volume and density of powder and solid materials. An inert gas (helium) is used as a displacement medium.