91 Mixing Matter-High

Mixing Matter Written by Lance Campbell

Introduction Look at the things around you. You probably see things with many different properties. You may see books, a chair, and some water. All these things are types of matter. A balloon and the air you blow into it are types of matter. Everything in the universe that takes up space and has weight is made of matter. But what exactly is matter? And what makes the many kinds of matter different? How can matter be mixed to create new things? This book explores these and other questions to help you better understand what matter is and how it can change.

Elements All matter is made of simple substances called elements. An element is a substance that cannot be broken down into a simpler substance. There are about 120 known elements on Earth. Substances can be made of a single element. Pure iron, gold, and silver are each made of a single element. They cannot be made into simpler substances. But most substances we know of are a combination of two or more elements. Sugar is a substance made of three elements, while salt is a substance made of two elements. This means that both sugar and salt can be broken down into the simpler elements they are made of.

Each element can be identified using a symbol. Many symbols are the first one or two letters of the element's name. For example, helium is "He," carbon is "C," and oxygen is "O." The images above show some common elements and their symbols. Word Wise Some symbols for elements come from Latin. Fe is the symbol for the element iron. Fe is short for ferrum, the Latin word for iron. Au is the symbol for the element gold. Au is short for aurum, the Latin word for gold.

Atoms Imagine that you had the power to look deep inside any substance or material. If you had this power, you would see that all matter, and therefore all elements, are made of tiny, invisible particles called atoms. Different elements are made of different atoms. Atoms are the smallest part of an element. If you could look into a gold coin, you would see that it is made of millions of gold atoms. If you could see inside a balloon filled with helium, you would see that the helium gas is made of millions of helium atoms.

Let's further imagine that you had super powers that let you see inside an atom. You would see that atoms are made of even smaller particles. The structure of an atom is in some ways like the structure of the Solar System. In the solar system, planets orbit, or go around, the Sun. In an atom, tiny particles called electrons orbit the nucleus, or center of the atom. The nucleus of an atom is like the Sun around which planets revolve. The nucleus is made of two kinds of particles— protons and neutrons. All atoms of the same element have the same number of protons and electrons. As tiny as atoms are, they have mass. Most of the mass of an atom is in the nucleus. So the more protons and neutrons an atom has, the more mass it has. A helium atom has 2 protons and 2 neutrons in its nucleus. This makes helium the second- lightest element. (The lightest is hydrogen.) Lead, on the other hand, has 82 protons and 125 neutrons, so it is much heavier than helium.