KEY IDEAS

• Air is a material
• Air has mass
• Air can be measured

EXAMPLE QUESTIONS

• How can you tell air is a material?
• How do you think air could be weighed?

AIR IS A MIXTURE OF INVISIBLE GASES

• Air is all around us.
• It is an invisible mixture of gases, and it takes up space.
• (An Empty drinking glass is not really empty; it is full of air).
• Air, or any gas, consists of tiny moving particles, called molecules.

AIR HAS MASS

• Like all substances, air has mass that can be measured (as shown on the video clip).

AIR CAN MAKE THINGS HAPPEN

• Moving air can make objects move.
• Air movements can be used as a source of energy to drive machinery, such as windmills or sailing boats.
• Wind is a large volume of moving air.
• We can make air move with fans, hair dryers, vacuum cleaners and bicycle pumps.