How to work with Newton’s Laws

You will have heard of Newton’s Laws in your Physics lessons. But what do you know about his theory of gravity?

The Greeks used to believe that the solar system was controlled by a God. Sir Isaac Newton apparently realised what gravity was when he saw an apple fall from a tree. He deduced that a force must be pulling it down to Earth. He wondered whether this force existed outside the Earth and into the rest of the solar system. In 1632 he put forward his theory of gravitational force.

If gravity just disappeared (which is nearly impossible) it is likely that the Earth would break into pieces and things like rivers would just float away. We have evolved with gravity present so our bodies cannot cope without it. When we stand up – our muscles are holding us up against gravity. If this did not happen, we would lose bone mass, and our muscles would lose strength. They would have nothing to work against! If we did not use our muscle, or have to hold ourselves upright, we would also lose our sense of balance. Astronauts can only stay in space for a certain amount of time so that their bodies do not suffer too much!

GCSE scientists, you need to know all about forces and motion, and be able to explain Newton’s Laws. For help with this, try our new guide, “How to work with Newton’s Laws”. The guide includes an explanation of Newton’s first, second and third Laws. As always there are questions to try, and answers to check your understanding.