Through hands-on experiments, students show that air takes up space and has weight, just like solids and liquids, proving that it is a real form of matter.

Key Ideas

• Air passes both tests for matter: it takes up space, which is why an upside-down cup pushed underwater stays dry inside, and it has weight, which is why a full balloon is heavier than an empty one.
• Air shows up in daily life in many ways. When it moves, we call it wind. We pull it into our lungs with every breath and push it back out. It inflates tires, sports balls, and balloons.

Supplies for Live Class:

• Balance scale, bubbles, straw, cup of water, fan, balloon (2)
• Alternative to balance scale: stick/dowel balanced on a string OR a hanger 
• Bowl of water big enough for you to stick your hand in: 
• Optional: a cup 

Vocabulary

• Mass: The amount of matter something is made of.
• Weight: How hard gravity is pulling on an object's mass.
• Air pressure: The force of air pushing on the surfaces around it.
• Atmosphere: The layer of air surrounding Earth, held in place by gravity.
  
  

Discussion Questions

• We know air has weight, but we do not feel it pressing down on us constantly. Why not?
• How would life on Earth be different if our atmosphere were ten times thicker?
• If air has mass and weight, why is it so much harder to measure the weight of air than the weight of a rock?

Hands-On Activity: Balloon Rocket

Lab Sheet 

Supply List

• One long piece of string or fishing line (at least 10 feet)
• One balloon
• A plastic straw
• Tape
• Two chairs or anchor points to tie the string across the room

Instructions

• Tie the string tightly between two chairs or anchor points across the room so it is pulled taut.
• Thread the straw onto the string before tying off the second end.
• Inflate the balloon fully but do not tie it. Pinch the end shut and tape the balloon to the straw while keeping the end pinched closed.
• Position the balloon at one end of the string. Let go.
• Observe how far and fast it travels. Try again with the balloon inflated to different sizes and compare.
• Discuss: what is pushing the balloon forward? If air were not real matter, what would happen when you released it? What does this prove about air?

Sources

• Nebel, Bernard J. Building Foundations of Scientific Understanding. A-3 Air Is a Substance and the Concept of the Atmosphere
• Air - Is it really there? (2022, June 17). [Video]. TeachEngineering.org. https://www.teachengineering.org/activities/view/cub_air_lesson01_activity2
• Gbh. (2022, June 14). Air is matter. PBS LearningMedia. https://virginia.pbslearningmedia.org/resource/phy03.sci.phys.descwrld.lp_air/air-is-matter/
• Air Facts for Kids. (n.d.). https://kids.kiddle.co/Air