Three states of matter

All materials is made from tiny particles. These particles are constantly moving. The kinetic theory uses this idea if tiny moving particles to explain the different forms that material can take. “Kinetic” means “to do with movement”. The three states of matter are solid, liquid and gas.

Solid. In this states matter tends to keep its shape. If is squashed or stretched enough, it will change shape slightly. Usually, any change in volume is too small to be noticed. The particles are not moving around, although they are vibrating very slightly. Normally they vibrate about fixed positions. If a solid is heated the particles start to vibrate more. The particles in a solid are fixed in position. The forces between particles are strong.

Liquid. In this states matter will flow. It will take up the shape of any container it is put in. The liquid fills a container from the bottom up. It has a fixed volume If the liquid is squeezed it will change shape , but the volume hardly changes at all. The particles, like those in a solid ,are vibrating. However, in a liquid the particles are free to move around each other. If a liquid is heated, the particles move faster. In liquids particles can move past each other. They are joined together in small groups. They are not as close as in solids.

Gas. In this states matter will take up the shape of a container and fill it. The volume of the gas depends on the size of its container. If the gas is squashed it will change both volume and shape. The particles are free to move around , and do not often meet each other. The particles whiz(z) around very quickly. If heated they move even faster. In gases there are hardly any forces between particles. They are a long way apart.

ENERGY

Energy is produced when matter is moved or changed. The change can be physical or chemical. If we heat ice it turns into water. If we continue heating the water ,it turns into stream. We call this change a physical one the same: two atoms of hydrogen and one atom of oxygen. Whenever new molecules are formed, a chemical change takes place.

When coal burns, heat energy is produced. Heat and light are produced by the chemical change. They are forms of energy. Besides these two forms of energy there are some other forms for which we have different names, such as mechanical energy , chemical energy, sound, electricity and nuclear energy.

One fact that makes all forms of energy so interesting and useful is that energy can be changed from one form into another. For instance , we have many ways for converting some forms of energy into electricity. The mechanical energy of falling water, the heat energy if burning coal or the heat energy of nuclear reactor are used to run an electricity- generating plant.

In all transformation of energy from one form into another the amount of energy remains the same after the transformation as it was before. This is the law of conservation of energy ,which states that energy can neither be created nor destroyed.