89 Mixing Matter-Low

Mixing Matter Written by David Dreier

Introduction Look at all the things around you. Maybe you see books, a chair, and some water. All these things are made of matter. Anything that takes up space and has weight is made of matter. But what exactly is matter—what is it made of? This book explores that question. It also looks at some of the ways that matter combines to create the many materials and objects in our world.

Elements All matter is made of elements. Elements are very special materials. They cannot be broken down into other substances. Imagine cutting a piece of gold into very tiny pieces. No matter how small a piece is, it will still be gold. That is why gold is an element.

There are about 120 elements. Some are metals such as iron and gold. Others are usually gases, such as oxygen and helium. Each element has a symbol. The symbol is one or two letters. The letters are often short for the element's name. For example, oxygen is "O." Helium is "He." Elements combine in many different ways. They make materials that we see and use every day. Word Wise Some symbols for elements come from the Latin language. For example, Fe is the symbol for iron. Fe is short for ferrum, the Latin word for iron.

Atoms Imagine that you could look deep into any object. You would see that everything is made of tiny particles. These particles are called atoms. Atoms are very, very small. They can only be seen with strong microscopes. The smallest part of an element is an atom.

Now imagine that you could look inside an atom. You would see even smaller bits. These bits are called protons, neutrons, and electrons. Protons and neutrons are at the center of the atom. The center of an atom is called the nucleus. Electrons circle the nucleus. All atoms of the same element have the same number of protons and electrons.