Scalars have a size, while vectors have both size and direction. When adding vector quantities, it is possible to find the size and direction of the resultant vector by drawing a scale diagram.
A scalar quantity can be described fully by stating its magnitude (size). Examples of scalar quantities are:
massThe amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g).
temperatureHow warm or cold something is.
distanceNumerical description of how far apart two things are. For example, the distance from Edinburgh to Glasgow is approximately 50 miles.
timeTerm that describes the order and duration of events. For example, the Physics lesson was 50 minutes long.
speedThe distance travelled in a fixed time period, usually one second.
energyThe capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow.
The quantities we write as \(15^{o}C\), \(75 kg\) or \(3 m\,s^{-1}\) are all scalars.
