In trying to make sense of the universe, scientists have classified everything that exists into two broad categories: matter and energy. Simply stated, matter can be thought of as “stuff” and energy is “the stuff that moves stuff.”
Matter is anything made of atoms and molecules; it has mass and takes up space. Even though matter can be found all over the Universe, you only find it in a few forms. We'll be learning about three types, or “states of matter”: solids, liquids and gases.
Matter can change from one state to another. One way is called a “physical change.” which usually occurs when energy is either added or taken away. Physical changes do not form new products and are reversible. The other way is called a "chemical change" which involves chemical reactions, the creation of new products and is typically irreversible. Chemical changes can be used to observe and measure chemical properties. There are numerous chemical properties of matter such as solubility, flammability, chemial stability and many more.
Sounds simple, right? Well don't go to sleep yet because there's a lot more to learn in the world of science.