What is Matter?
Grade 7 Science
Ms. Willis - Lawfield
• I can explain the particle theory of matter.
• New vocabulary: matter, chemistry, particle theory, solid,
liquid, gas, changes of state
Learning Goals
Anything that has mass and takes up space.
• This includes anything you have ever touched, tasted and
smelled. Think wood, steel, ice, shampoo, milk, your
entire body!
What is Matter?
• Chemistry: The study of matter and its changes
• People who work in medicine, cooking, art, photography,
and solving crime all use chemistry in some way
• We use many human-made chemicals (eg. Almond
extract, lemonade)
The Science of Matter
• All matter is made of tiny particles. Different kinds of
matter are made of different kinds of particles.
• Each particle does not look like the kind of matter they
make-up, but when large numbers are put together they
look and behave like a piece of matter.
• The picture below shows tin foil under a microscope
where you can begin to see the particles.
The Makeup of Matter
• Definition: An explanation of what matter is made of and
how it behaves; the particle theory states that all matter
is made up of tiny particles that are always moving, that
attract each other and that have space between them.
The Particle Theory of
• 1. All matter is made up of tiny particles
• 2. Particles have empty spaces between them.
• 3. Even though you cannot see them, particles are always
moving randomly all the time.
• 4. Particles move faster and spread farther apart when
they are heated.
• 5. Particles attract each other, so they tend to stay
together rather than fly apart.
5 Main Ideas of Particle
• This theory helps explain many puzzling observations.
For example, when we put a few drops of food colouring
in a jar, the food colouring mixes into the water without
even stirring.
The Particle Theory
• Matter behaves very differently in each state of matter.
• 1. Solid: A state of matter with a definite volume and a
definite shape. (recall the definition of volume – a
measure of the how much space occupied by an object)
• 2. Liquid: A state of matter with a definite volume but
no definite shape; takes the shape of its container.
• 3. Gases: Does not have a definite volume or shape;
takes the shape and volume of its container.
Three States of Matter
• The particles of a sample of matter always stays the same,
whether the matter is solid, liquid or gas. The difference
is that particles move differently in each state.
• Solid: the particles are close together and vibrate rather
than moving around. (think movie theatre rows of people)
• Liquid: The particles are still close, but they move
around each other.
• Gas: Particles are very far apart and move very fast in all
directions with lots of energy.
Particles of Solids,
Liquids and Gases
Particles of Solids,
Liquids and Gases
• Changes in states of matter happen when matter is heated
or cooled.
• Discuss the changes of state for water.
Changes in States of
• States of Matter Song Song!
Let’s Review!

Classifying Matter - Grade 7 Science is Awesome!