Matter is anything that has mass and takes up space. It includes all the physical “stuff” around us—rocks, houses, water, air, people, ants, trees, etc. All matter can exist as a solid, a liquid, or a gas. Matter includes all the things we can weigh (to find the mass) and measure to find the volume (because they take up space).
Different substances—different types of matter—have different properties that can be used to distinguish them from each other. These properties are things that you can observe or measure about the substance. For example, water and isopropyl alcohol (rubbing alcohol) are both clear, colorless liquids at room temperature. However, they can be told apart because they have other properties that are different. Water is odorless while the isopropyl alcohol has a strong smell. The alcohol evaporates very quickly while the water evaporates slowly. Also, the alcohol is flammable—it can be set on fire with a match (but don’t try this at home!). Water, on the other hand, is not only inflammable; it is used to put out fires.
The properties of matter can be divided into two categories: physical properties and chemical properties. Physical properties can be observed or measured without changing the composition of the substance. An example is odor. When you smell water or isopropyl alcohol, neither of these substances changes into something else. They remain water and isopropyl alcohol. Similarly, when water and isopropyl alcohol evaporate, they do not change into something else. They move from liquid into gas, but the water is still water and the alcohol is still alcohol. Because these substances do not change into different substances, the properties of odor and speed of evaporation are physical properties.
Here are some other examples of physical properties. Copper is a substance that is a solid metal at room temperature with a melting point of 1083°C. It is shiny, bendable, and orange-brownish-colored. It can be flattened into a very thin sheet of metal or it can be stretched into a thin wire. It can conduct heat quickly and it can conduct electricity, which is why copper is used in power cords and other wires.
All of these properties of copper are physical properties because the copper does not change into anything else when these properties are observed. You can see that it is a solid and shiny without doing anything to it. You can bend, flatten, or stretch, it. These actions will change the shape and appearance, but it remains copper. Even heating it until it melts into a liquid or running electricity through it will not change the copper into another substance.
As mentioned above, some properties are chemical instead of physical properties. In this type, the substance actually changes into another kind of substance. The flammability of isopropyl alcohol is an example of a chemical property. When alcohol is burned, the alcohol actually turns into something else. At the end of the change, the alcohol is gone and has been replaced by carbon dioxide (a colorless gas) and water vapor (water that is in the gas state). This is not a physical property because the isopropyl alcohol is changed into something else.
Which of these is not a physical property of water?
Which of these is a physical property of the metal aluminum, out of which aluminum foil is made?
True or false? When water is heated to its boiling point of 100°C, it bubbles and appears to disappear into the air. This is an example of a physical property.