Forces, motion and energy

Forces

Forces and their effects are all around us. They keep us firmly rooted to the ground, they make us move and they stop us slipping and sliding. Forces are vital to life and the universe.

However, forces only do three very simple things. They change:

  • the shape of an object
  • the direction of an object
  • the speed of an object

If you crumple up a piece of paper, you have changed its shape. If you throw the paper ball, you have changed its speed. If you ask a friend to bat it away, they have changed its direction.

Force is measured in the unit called Newtons (N) – named after the first scientist to quantify forces, Sir Isaac Newton.

We can measure force using a special piece of equipment called the Newton Balance.

The Newton Balance looks like a thermometer with a hook at the bottom and an indicator. The measurements are in Newtons. When an object is placed on the hook the indicator moves downwards.