Monday 11/15/10 Air in a Syringe DateAssignmentPage 11/12

What we will do today… 1.We will review the terms compression and expansion. 2.We review the idea of matter being made of particles. 3.Identify how particles can help explain what happened to the air in our syringe system.

How we will do it… One activity Group discussion Writing answers to questions Whole class discussion

Air is a mixture of gases. The gases in air have mass and occupy space. Air is matter. Air can be forced into a smaller space. This is compressed air. When the force holding air in a smaller space is removed, the air expands. When matter expands, it takes up more space. A given mass of compressed air occupies less space than the same mass of air when it is expanded.

Air, like all matter, is made of tiny particles too small to see. The particles of air, like the particles of all forms of matter, are in constant motion. The particles of air are not touching one another. There is space in between them. Because the particles are in constant motion, they bounce off one another and the sides of their containers all the time. In your next activity, try to visualize the particles.

Syringe and Bubble System Drop one bubble into the syringe barrel. Insert the plunger half way into the barrel. Clamp the tubing to make a closed system. Apply force to the plunger. Think about what is happening to the syringe, to the air in the syringe, and to the air in the bubble. Try to explain what is happening.

Expansion and Compression 1.What is inside the syringe? 2.What is in the bubble? 3.What happens to the air in the syringe when push down on the plunger? 4.What happens to the bubble when push down on the plunger? 5.Why does the bubble shrivel up? 6.What happens to the bubble when you pull on the plunger?