What is the scientific definition of energy?

In the study of physics, energy is defined as the capacity to do work. That energy or force is measured in units called joules.

Work involves the application of force on an object that causes movement across a distance. For example, pushing a shopping cart involves exerting force to move it over the ground. The basic equation to illustrate this is:

• Work done = force x distance, or
• W = F x d, with W being work done in joules, F being force in Newtons and d measured in meters.

The activity of work essentially involves the transfer of energy. In the previous example, energy is transferred from a person to the shopping cart.