Tutorial 1: Scalars
> Flow Scalar
A scalar is any dimension measured with respect to time. The three main types that we will discuss are Flow, Volume and Pressure.
Flow is defined as the volume of gas passing a certain point in a given amount of time. It is usually measured in Litres/minute. The video on the right simultaneously displays the tracing of the flow scalar and the movement experienced by the lungs. Notice that flow is positive during inspiration and negative during expiration. This is because the direction of air flow reverses.