1. Mr. Chapman Science 10

2. It may be surprising, but air is a fluid. Definition of Fluid: a substance, as a liquid or gas, that is capable of flowing and that changes its shape at a steady rate when acted upon by a force tending to change its shape. As you may already know, fluids exert PRESSURE on their surroundings. The air we breathe is no different; it exerts pressure on everything around us. AIR PRESSURE IS APPROXIMATELY 15 LBS/INCH 2

3. Air Pressure & Air Speed Air speed: The speed at which air is travelling Their is a direct relationship between air speed and air pressure, and the goal of today’s activity is to determine how air pressure and air speed are related. Once you know the answer to this question, you should be able to explain why the roofs get blown off of these houses: http://www.youtube.com/watch?v=lJbz0EuUSlA http://www.youtube.com/watch?v=7K-ctyHRC1s

4. Set up two cans on straws as seen in the picture above. Blow air between the two cans. What do you observe?

5. Fill a 400 mL beaker with approximately 300 mL of water Place a straw in the center of the beaker with water; hold the straw up in place With another straw, blow air across the top of the straw that you are holding in place. What do you observe?

6. ** Perform this activity over a sink Note: This activity has nothing to do with air speed, but has EVERYTHING to do with air pressure. Fill a water cup approximately half-full with water Place a coaster over the top of the cup and hold it tightly over the sink as you FLIP THE CUP OVER. Release the coaster (OMG) WHAT DO YOU OBSERVE?

7. In-Class Conclusion State the purpose / goal of the 3 activities that you performed in class on Friday. Describe what you observed at each station. Explain in general terms what was occurring with relation to air speed and air pressure at each station based on your observations. Note: although activity 3 had nothing to do with air speed, explain what was occurring anyway. What general principle can you deduce based on your observations and explanations for each activity? Explain why high wind speeds cause the roof of a house to come off based on the conclusion from the 3 activities.