Basic Concepts
In a nutshell: Matter is anything that has mass and takes up space, forming everything in the universe.
## The Building Blocks of Everything
Matter is anything that takes up space and has mass. This means that everything you can touch, see, smell, or even taste is made up of matter! Matter is all around us—your desk, your pet, your lunch, and even the air you breathe.
## States of Matter
Matter commonly exists in three states:
- **Solid:** Keeps its shape and volume (like an ice cube).
- **Liquid:** Takes the shape of its container but keeps the same volume (like water).
- **Gas:** Fills its container and can be compressed (like the air in a balloon).
Scientists have even discovered other states, like plasma and Bose-Einstein condensates, but you'll mostly see solids, liquids, and gases in daily life.
## Tiny Particles: Atoms and Molecules
Matter is made of **atoms**, which are the smallest units of ordinary matter. Atoms can join together to form **molecules**. For instance, two hydrogen atoms and one oxygen atom make a water molecule (\(H_2O\))!
## Why Does Matter Matter?
Understanding what matter is helps us explain why things behave the way they do—why ice melts, why water boils, and why a basketball bounces.
Examples
- Water is a liquid, ice is a solid, and steam is a gas—all forms of matter.
- A wooden chair, the air in your room, and your favorite snack are all matter.
Key terms
- Atom
- The smallest particle of an element that retains its properties.
- Molecule
- A group of two or more atoms bonded together.
- Solid
- A state of matter with a definite shape and volume.
- Liquid
- A state of matter with a definite volume but no definite shape.
- Gas
- A state of matter with no definite shape or volume.