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Big Idea: The behaviour of matter can be explained by the kinetic molecular theory and atomic theory.

Air conditioner and plant

Humidity: Outdoors and Indoors


Learn about the importance of humidity, its sources and how people control it indoors.

Katie Mack headshot

Katie Mack (she/her)

Career Profiles

Hawking Chair in Cosmology and Science Communication

I study of the fundamental physics of the universe.
physical and chemical changes header

Exploring Physical and Chemical Changes


Students observe and classify physical and chemical changes of matter.

Sea ice

Ice on Earth - The Cryosphere


Learn about the cryosphere and how it is being impacted by climate change.

Hand writing chemical equations

Chemical Equations


Learn about how to write and balance chemical equations.

Heating a liquid over a flame in a lab

Types of Chemical Reactions


Learn about the four main types of chemical reactions.

Periodic Table with molecular model

Introduction to the Periodic Table of the Elements


Learn about the elements of the periodic table and how they are organized.

Cloud model of an atom

Introduction to the Atom


Learn about the parts of an atom and its history.

Cube overflowing with spheres representing particles

Introduction to the Particle Theory of Matter


Learn about how the Particle Theory helps us understand matter.


Weather: Precipitation


Learn about humidity and the many forms of precipitation.

Ice technician on a zamboni at an outdoor skating rink

The Hidden Heroes of Hockey!

STEM Explained

Ice Technicians use math and physics in order to keep the ice ready for hockey.

Casting hot iron

What Causes Hot Things to Glow?

STEM Explained

Getting electrons excited by heat can cause certain materials to give off visible light when heated - like filaments in light bulbs.

Solid, liquid and gas

States of Matter


Learn about the states of matter, as well more about one state in particular - gas!

People playing ice hockey

Why Do Ice Rinks Stay Frozen?

STEM Explained

Every ice rink is an example of molecular bonding and gas laws at work!

Why is rain not salty?

Why is rain not salty?

Hands-on Activities

Make a model of the water cycle and find out how water moves around on planet Earth.