Everything in this entire universe is controlled by forces and these forces are either a push or a pull.
Forces are what move planets about in space, what makes the tides of the oceans come in and out and what makes the wind blow.
Gravity is a force that pulls things down to the Earth.
Magnetism is a force that pulls objects near or pushes them away.
Friction is a force that heats things up, like when you rub your hands together.
Springs and elastics are also types of forces. When you push against them they resist and then they spring back with exactly the same force you gave them.
The bigger the force, the more powerful it is. When you push a friend on a swing that’s a push force, the harder you push the further the swing goes.
When you open a door you use a pull force.
Another force is pressure. When you step on a pile of grapes, the weight squashes them or when you step on snow, the pressure leaves footprints.
Different types of forces often work at the same time. If you throw a ball, there is the force of you throwing it which is moving it forwards, there is the force of gravity pulling it down to the ground and there is the force of air resistance slowing the ball down. Three forces are working at the same time!
Force is measured in newtons. The instrument used to measure the size of a force is called a newton meter or force meter.
Isaac Newton was one of the first scientists to study force and gravity. He created three laws called 'Newton’s Three Laws of Motion':
- A body in motion is likely to stay in motion. A body in rest is likely to stay at rest. For example, if you’re watching a really fun cartoon on TV, you’re likely to continue watching it unless some motion stops you.
- If a force acts upon a body, it will change the body’s speed or direction. An example of this is if you kick a ball, the ball will either go faster or change direction.
- For every force and action, there is an equal reaction. If you kick a ball softly it won’t go far but if you give the ball a big kick it will.