MATTER
Everything is made of matter. Every object, substance, chemical and material is matter. This includes not only things you can see easily, like the paper of page and the ink that forms the words and pictures. It also includes specks of dust too small to notice, houses and cars, living things like trees and your own body, the rocks of the Earth, the clouds in the sky and the invisible air around you. And not only objects and substances on Earth are made of matter. All of the planets and stars in deep space contain matter. In fact everything in the entire Universe is made of matter. All matter is made of tiny building blocks called atoms.
There are places where there is no matter. If there is no matter then there is nothing at all. The total or complete absence of matter is called a vacuum. However a total vacuum is very unusual. “Space” is named because it is supposed to be just empty space, with no matter. But even in the depths of space, a few micro-particles of dust or some wispy bits of gas are floating about. These tiny bits of matter may be several metres apart, instead of crammed together like they are on Earth. But they are still present. Here on Earth, powerful vacuum pumps can suck most of the matter out of a container, but never quite all of it.
Why is a butterfly like a lump of rock whizzing through space? Both are made of atoms. The butterfly is living matter, the rock non-living matter.
STATES OF MATTER
Matter exists in three main forms, called the states of matter. These are solid, liquid and gas. In a solid such as ice, the molecules are very close together and joined in a rigid pattern. They can hardly move. So a solid object stays the same volume and does not change its shape. In a liquid such as water, the molecules are still quite close together but they are not joined to each other. They can move about, which means the whole liquid can change shape and flow, although, like the solid, it still takes up the same volume. In a gas like water vapour, the molecules can move nearer together or farther apart. So a gas can also get bigger or smaller, to fill the container it is in.
A hot-air balloon contains matter in the form of gas – air. Heat from the burner causes the air’s molecules to rush farther apart, so taking up more room. Soon there are fewer molecules in the hot air inside the balloon than in the normal air outside. The balloon is lighter or less dense and rises.
CHANGING STATES
Matter or substance can change state from solid to liquid, or liquid to gas. This usually happens by adding heat. Matter can also change state the other way from gas to liquid or liquid to solid. This usually happens by cooling (taking away heat). A common example which is all around us is water. The world’s water is always on the move and changing state in a never-ending process, the water cycle.
In the water cycle, the Sun warms the sea. The heat makes liquid water turn into a gas, invisible water vapour, which rises into the sky. It is cooler high up so water vapour changes state back into a liquid, forming tiny droplets. These are so light that they float as clouds. Wind blows the droplets over the land. Some clumps together, become too heavy to float and fall as rain. Some droplets blow even higher, up over a mountain, and become even colder. They change state again, freezing solid into snowflakes. The snow falls to the ground and melts into liquid water. With the rain, it flows into streams and rivers, and finally into the sea and so the cycle continues.
PROPERTIES OF MATTER
Matter has many features, or properties. One of the main properties is its state -solid, liquid or gas. Another property is the type of atoms it is made of. Each kind of pure substance, like iron, carbon, oxygen or sulphur, has a different kind of atom. It is known as a chemical element.
A third property of matter is density. This is the amount of matter in a certain place or volume. The more matter within a certain volume, the denser or heavier the substance or object. Dense substances like iron have lots of large atoms packed close together. Density is important because it determines whether things float or sink. If an object is less dense than water, such as a lump of wood, it floats. A lump of iron is more dense than water and so it sinks. But if the iron is made into a boat’s hull its shape contains lots of air, which has a very low density and is extremely light. The overall density of the iron-plus-air is less than the density of water, and makes the boat float.
Picture Credit : Google
