Forces Motion And Energy: Science Terms Explained

Plain-language definitions of every forces motion and energy term your child meets in school, each with kid-friendly explanations, worked examples, and common mistakes to watch for.

Mass and weight

Mass and weight are related but different: mass is how much matter is in an object, and weight is the force of gravity pulling on that mass.

Mechanical energy

Mechanical energy is the total energy an object has because of its motion and its position, which is found by adding its kinetic energy (energy of motion) and potential energy (stored energy due to position).

Momentum

Momentum is the quantity of motion an object has, calculated by multiplying its mass by its velocity, and it describes how hard it is to stop or change that object's motion.

Motion

Motion is a change in an object's position over time compared with something else, which shows that the object is moving rather than staying still.

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