Physical Attributes
Change over time of physical attributes can be represented as a time function.
Examples:

The trajectory of an airplane is represented as
Position: Time →
Reals^{ 3}_{}
where Position (t) = (x(t), y(t),
z(t)) is its position at time t ∈
Time. Its position and velocity are represent by the function
f: Time → Reals^{
6}
where f(t) = (x(t), y(t), z(t),
v_{x}(t), v_{y}(t), v_{z}(t)).

A weather map is a function
AirTemp: X ×
Y → Temperature
where X × Y '
Reals^{2} is the area of interest and AirTemp(x,
y) is the temperature at location (x, y).