Energy and Forces

Energy and Forces

Energy is the ability to cause changes and make things happen. It comes in many forms, including movement, heat. light, sound, nuclear, electricity, magnetism and gravity.

Energy is not a single object or feature. It exists in many forms with different names. Kinetic energy is caused by the movement or motion of an object. It depends on an object's mass and speed. For example, a buzzing fly has much less kinetic energy than a speeding express train. Potential energy is caused by an object's position or state. A stretched elastic band has potential energy, ready to convert into a force that causes movement.

Transforming energy
Energy changes or transfiamns from one kind to another. A big rock at the top of a hill has potential energy. As soon as the rock starts to roll this becomes kinetic energy Electrical energy passing through a light bulb is transformed into fight energy and heat energy With each transformation, the total amount of energy at the end is usually the same as at the start. This is known as conservation of energy.

Forces
A force is a push, pull, squeeze or stretch that makes an object move, alters its speed or direction, or changes its shape. A football does not move until a player provides a force by kicking it. Then the ball picks up speed and flies through the air. Then other forces-especially the Earth's gravity gradually slows the ball down. The ball also slows down due to the resisting force of the gas particles or molecules in air, which it must push out of the way as it moves through them.

Fascinating Fact
Scientists recognize four main, or fundamental, forces that work throughout the Universe.
• Gravity or gravitation: Attracting force which draws any two objects or pieces of matter together.
• Strong nuclear force: This holds together particles in the centre, or nucleus, of an atom.
• Weak nuclear force: This allows atoms to change from one type to another and give out energy.
• Electromagnetic force: Produced by a combination of electricity and magnetism.