Describing Matter (SOL 3.3)

Describing Matter (SOL 3.3)

What makes up the world around us? People have asked this interesting question for thousands of years. Scientists know that everything is made of matter. Matter is defined as anything that has mass and takes up space. The amount of space an object takes up is called its volume. Both living and non-living things are made of matter. Everywhere you look, you will see different kinds of matter.

We describe and classify the many types of matter by their physical properties. A physical property is a characteristic or trait that can be observed using the five senses. An object’s physical properties include its size, color, smell, or texture, for example. We also describe matter by taking measurements such as volume, length, or weight. Weight tells us an object’s mass, or how much matter it contains.

Changing Matter (SOL 3.3)

Different materials each have their own unique physical properties. We can change some physical properties of an object, like its size or shape. But when we do this, other physical properties stay the same. Think about breaking off a chunk of a chocolate bar. The little piece tastes, smells, and looks the same as the entire candy bar.

What happens when we combine different kinds of matter? This forms a mixture, but the physical properties of each material stay the same. Sometimes we can see all the parts that make up a mixture, like when we mix cereal and milk. A special kind of mixture called a solution occurs when one material dissolves into the other. It breaks down into such small parts that it mixes evenly and we cannot see the separate materials. This happens when we add powdered drink mix to water, for instance.

States of Matter (SOL 3.3)

There are three states of matter: solids, liquids, and gases. A solid has a definite volume and shape. This means that its shape and volume stay the same. A liquid has a definite volume, but it can change its shape. Liquids flow and will take the form of their container. Unlike solids and liquids, a gas expands to fill up the space around it. It does not have a definite shape or a definite volume.

In solids, liquids, and gases, the tiny particles that make up matter do different things. These tiny particles are called molecules. They are made of even smaller bits called atoms. In solids the molecules are close together. Molecules are farther apart in liquids and can move a little. In gases, the molecules are very far apart and move quickly, so a gas can fill the space it is in. That’s why a gas can change volume.