It is tempting to think that some materials are always heavier than other materials. For example, someone might say that metal is heavier than air. But it depends on how much of each material there is ...

The density of an object or substance is its mass divided by its volume: Density = Mass ÷ Volume. The units of density depend on the units used for mass and volume, but are usually: g/cm³ (if mass is ...

Discussions about batteries often revolve around energy density. What we want is a battery that stores a whole lot of energy in a very tiny volume, preferably in a manner that doesn't involve ...

Power density is a term that more or less defines itself. For a more formal definition consider this: Power density is a measure of the amount of output power of a circuit or device divided by the ...