Energy is the ability to make things happen and cause changes. It exists in many forms, such as sound, light, electricity, and chemicals. Moving objects also possess a type of energy, kinetic energy. Using energy and principles of mechanics and movement, we combine simple machines, such as levers and wheels, into enormously complex ones.
About energy
You can’t see energy. You can’t touch it or hold it in your hand. But energy is Everywhere. Energy neither can be created nor can be destroyed. It changes one form to another form. Energy is the ability to do work, to make things happen, and to cause changes. There are many different types, or forms, of energy. A hot drink has heat energy. A flash of lightning during a thunderstorm has both electrical and light energy. A lion’s roar is sound energy. A racing car speeding around the track has movement energy, which is also called kinetic energy. Even a book lying on a shelf has energy. Because of its position and the pull of gravity, it presses down on the shelf. This type of energy is called potential energy.
Radio energy
Radio and television programs are received by aerials, which pick up invisible waves of energy sent out by transmitters. The waves consist of electrical and magnetic energy, so they are called electromagnetic waves. Some transmitters are fixed to the tops of tall towers so that the radio waves of energy they send out can travel very long distances.
TYPES OF ENERGY
- Chemical energy, contained in atoms and molecules.
- Kinetic energy, in moving objects.
- Potential energy, from an object’s position.
- Sound energy, when atoms or objects vibrate.
- Nuclear energy, when atoms join or split apart.
- Electrical energy, from moving electrons.
- Magnetic energy, due to magnetic attraction.
- Electromagnetic energy, in the form of various kinds of rays or waves. These include radio waves, microwaves, heat, light, X-rays, and gamma rays.
Energy from the Sun
The energy we receive from the Sun is called solar energy. It consists mainly of light and heat that travel through space. These forms of energy come from atoms smashing into each other in the center of the Sun and joining together or fusing. This process is called nuclear fusion. The energy that comes from the centers or nuclei of atoms is called nuclear energy. The form of nuclear energy in nuclear power stations here on Earth comes from nuclear fission when atoms split apart.
Soaraway energy
A ski jumper soars into the sky, leaning forwards to cut through the air and fly as far as possible. The jumper gets the energy needed for such a huge leap by sliding down a tall hill faster and faster, changing potential energy into kinetic energy, then leaping from the upturned take-off ramp.
Energy for robots
Vehicle-building robots need the energy to move their mechanical arms. This is usually supplied by electricity, which drives electric motors, which tilt and swivel the arms. The movements are controlled with great precision by computer.
Movement energy
Anything that moves has kinetic energy. The faster it moves and the more substance or matter (mass) it contains, the more kinetic energy it has. A fast train speeding across the countryside has an enormous amount of kinetic energy.
