Matter

When a substance reacts with another and results in a completely new substance, a chemical change has happened. One of the most common ones is combustion. When you burn wood, it turns into ash and carbon dioxide. Also, when you leave a piece of metal outside for some time, it begins rusting. This is because it has interacted with oxygen, which when reacts with iron it creates iron oxide, a new substance.

Chemical Changes

What are chemical changes?

In simple words, matter is anything that takes up space. You, your desk, your phone, or anything that physically exists can be considered as matter.

Matter

What is matter?

Substances go through changes all the time, however, sometimes they only change the appearance of the substance without changing it’s identity. For example, when you leave a drink in the freezer for too long, it begins freezing. The drink now becomes ice, but it remains to be the very same drink, just that it’s solid and cold. Another example is when you break a pencil; it is now separated in two, but it is still a pencil.

Physical Changes

What are physical changes?

Gasses are the most "free" of the three states of matter. They are able to fit almost anywhere, and most of the time, they are invisible. The air we breath is a gas, so is the gas we use to cook at home and the gas released when burning a piece of wood, although that one is fairly visible. Their particles move around a lot and do not make up a definite shape.

Gasses

What are gasses?

Solids are objects that stay together no matter the container they're in. Their particles tend to be really close to each other and only "jiggle" in fixed positions. Ice, pencils, and books are only some examples of solids.

Solids

What are solids?

Liquids are objects that change their shape depending on the container they're in. Things like water, oil, and drinks are the most common examples of liquids. Their particles move around more than the solids, however, they are not completely "free".

Liquids

What are liquids?