1. What happens when air is heated?
Lesson 3

2. Lesson vocabulary Helium: a light, colourless gas that will not burn.
Hot air-ballon: a large bag of lightweight material that lifts into the air when it fills with hot air; the bag and burners for heating the air are collecting from a hanging basket.
Hydrogen: a light, colourless gas that will burn.
Molecule: the smallest unit that a substance can be divided into.

3. Lesson background Earth’s atmosphere is made up of gases.
Gases have neither a fixed shape nor a fixed volume; they fill up and take on the shape of a container.
Gases have weight, but are less dense than solids and liquids.

4. Lesson background Behavior of gases is explained by the kinetic theory
“All matter is made up of constantly moving particles”
Kinetic Theory:

5. Lesson background
Gas particles move faster when the gas is hot then when the gas is cold
Light-weight particles move faster than heavier ones at all temperatures

6. What Happens when Air is Heated?
Let’s look at the physics of hot air balloons to help us understand what happens when air is heated