Chemistry States of Matter
States of Matter
States of Matter
More than just your average solids, liquids and gases!
Introduction
When water turns into snow, is it still water? The answer is yes!
Our world is filled with solids, liquids and gases and matter can go from one state of matter into another without changing its substance. In this lesson, students explore the different states of matter.
Objectives
- Differentiate the 3 main states of matter.
- Explain the term “cohesion”.
- Understand the transitions between states.
Background
A “state of matter” is a way to describe the behaviour of atoms and molecules in a substance.
There are three common states of matter:
- Solids – relatively rigid, definite volume and shape. In a solid, the atoms and molecules are attached to each other. They vibrate in place but don’t move around.
- Liquids – definite volume but able to change shape by flowing. In a liquid, the atoms and molecules are loosely bonded. They move around but stay close together.
- Gases – no definite volume or shape. The atoms and molecules move freely and spread apart from one another.
Plasma is sometimes referred to as a fourth state of matter. While it’s similar to a gas the electrons are free in a cloud rather than attached to individual atoms. This means that a plasma has very different properties from those of an ordinary gas. Plasmas occur naturally in flames, lightning and auroras.
Other, more exotic states of matter can occur at extremely high energy levels or at extremely low temperatures, where atoms and molecules (or their components) arrange in unusual ways. Scientists also sometimes distinguish between crystalline solids (where the atoms and molecules are lined up in a regular pattern) and glassy solids (where the atoms and molecules are attached in a random fashion).
Each of these states is also known as a phase. Elements and compounds can move from one phase to another phase if energy is added or taken away. The state of matter can change when the temperature changes. Generally, as the temperature rises, matter moves to a more active state.
The word phase describes a physical state of matter. When a substance moves from phase to phase, it’s still the same substance. For example, water vapour (gas) can condense and become a drop of water. If you put that drop in the freezer, it would become a solid. No matter what phase it is in, it is always water — two atoms of hydrogen attached to one atom of oxygen (H20).
Entire Lesson
These resources are free!
You must LOGIN to download the full lesson + activities.
Other Resources
Science World Resources | Full Lesson | Air
Science World Resources | Full Lesson | Goo
Science World at TELUS World of Science | School Workshop | Chemistry