Solids have some properties that are unique to them. Melting point and solubility are two of them. Melting point is when a solid turns into a liquid. You see this a lot with butter and margarine. Margarine has a much lower melting point then butter, so melts better on foods that are barely warm. Sometimes you don't want something to melt easily. Flour has a much higher melting point, which it why is good to throw that on a fire to smother it. It will stay solid and create a blanket blocking oxygen.

Solubility is how well that solid dissolves in a liquid. Sugar dissolves well in coffee, but badly in oil. Some stains will dissolve better in alcohol than they will in water. Knowing what will dissolve in what liquid helps you figure out how to clean.

Density is how compact something is. A small chunk of lead is much denser than an identical sized piece of wood. Density is usually used with solids. Hardness is another way to compare solids. There is even a special scale to compare these. The lower the number, the softer the material. Talc is very soft whereas diamonds are very hard.

Liquids also have to deal with solubility. Oil and water is the clearest example. Both are liquid but are not soluble in each other. When you were making vinaigrette, you may notice that some spices dissolve in the oil better than in the vinegar. Liquids also have to deal with a freezing point. Knowing which liquids freeze at which temperature can help distinguish between them. We mentioned earlier that liquids will turn into gases at certain temperatures. Specific gravity is very similar to the density, but is usually used more with liquids. Your dish soap will have a higher specific gravity then the water in the sink. Maple syrup is much denser than milk, so it has a higher specific gravity.

Gases have vapor points, which is just the temperature that they turn into a liquid. It is basically the same thing as when liquid becomes gas, but in the other direction. Gases change in precise amounts when you change the temperature, pressure, and volume. A fair amount of the math in chemistry is used to predict exactly how a gas will behave given those changes. Generally, if you increase pressure or volume, temperature or concentration increases. This is clearly shown in hot air balloons. When you heat up the air inside, the volume increases.

Frequently matter has different color and odor. Sulfur and gold are both yellow, but the smell is easy to compare. Some gases can be compared by smell and color, but many of those are colorless and odorless. Not as many as we would like are odorless, but in the overall picture, they are. Usually, combinations of these properties are used to compare matter. Fool's gold shares many of the properties of regular gold, but differs enough for us to tell the difference. By listing and comparing the physical properties of a substance, you can frequently figure out what it is. Many chemistry experiments have you doing this.

You can occasionally change a physical property without changing its state. Hammering metal is one example. The metal will still be in the same state (solid), but hammering it will change how strong it is, without changing its chemical properties.

Substances also share chemical properties. We mentioned this earlier with the elements. While the element groups share some of the physical properties, they also share some of the chemical properties. Chemical properties describe the ability to form new substances under certain conditions. If you get any of the group one elements near water, they will explode. When wood burns, it is showing that at a certain temperature, it will react with oxygen and decompose.