Final answer:
Vertical expansion refers to an increase in height or vertical position, while vertical compression refers to a decrease in height or vertical position.
Step-by-step explanation:
Vertical expansion or compression can be determined by observing the changes in the height of an object or the compression of a spring. When an object or material is compressed vertically, it means that its height or vertical position is decreasing. On the other hand, when an object or material expands vertically, its height or vertical position increases.
For example, when a spring is compressed, its coils are forced closer together, reducing its overall length. This is a vertical compression. Conversely, when the spring expands, its coils move apart, lengthening its overall length. This is a vertical expansion.
In summary, vertical expansion refers to an increase in height or vertical position, while vertical compression refers to a decrease in height or vertical position.