Syringe Activity- How does air move? • Push & pull the plunger and make observations about how pressure feels and how air moves 1) With the Tube open 2) With the tube clamped shut – Is it harder to push the plunger in and pull it out with the tube open or clamped off? – What is causing it to be more difficult?
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Syringe Activity- How does air move? Push & pull the plunger and make observations about how pressure feels and how air moves 1) With the Tube open 2)
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Syringe Activity- How does air move?
• Push & pull the plunger and make observations about how pressure feels and how air moves1) With the Tube open
2) With the tube clamped shut
– Is it harder to push the plunger in and pull it out with the tube open or clamped off?
– What is causing it to be more difficult?
Model of Air molecules• http://www.youtube.com/watch?v=08ezkSr
When cup is completely filled with water, no air is
left in cup, thus no air pressure.
1)1) Pressure is in all directions.Pressure is in all directions.
2)2) High pressure outside pushes towards low High pressure outside pushes towards low pressure inside and holds card in placepressure inside and holds card in place
3)3) Air pressure can be stronger than water pressure Air pressure can be stronger than water pressure
The picture below is a “before and after” shot of a Styrofoam cup that was brought to a depth of 1770 ft. in the waters off the Gulf of Mexico on September 28, 1994. P = 5,500,000 Pa 1) What do you notice
about the cup that was brought underwater?
2) What might have caused the changes that you notice?
3) Does this suggest that water pressure behaves in one direction or all directions?
4) Do you think that water pressure is similar to air pressure? Why or why not?
Challenge:
Solution:
Results and Explanation:
How can cause a can to collapse?
Title: Activity 2. Collapsing Can Date: Feb. 2010
Summary:
Explain the principle behind the collapsing can.
Collapsing CanCollapsing Can
Before heating, the can was filled with water and air.
By boiling the water, the liquid changed into water vapor
The water vapor or steam pushed the air that was inside, out of the can.
In closing off the can, air is prevented from going back to the can.
Cooling (water in basin) condenses water vapor back to water. All the
vapor which took up space inside the can turned into a few drops of
water, which take up less space.
Pressure inside can drops allowing outside air pressure to push on the can and
crush it. http://www.youtube.com/watch?v=p3b9pK-O6cE&list=UUHnyfMqiRRG1u-2MsSQLbXA&index=22&feature=plcp
1)1) Pressure is in all directions.Pressure is in all directions.
2)2) High pressure outside pushes towards low pressure High pressure outside pushes towards low pressure inside and caused can to collapseinside and caused can to collapse
3)3) Air pressure can be strong enough to crush metalAir pressure can be strong enough to crush metal
2) Explain how a straw works for drinking. (When you drink liquid through a straw, is it accurate to say the liquid is sucked up the straw or pushed up the straw?)
3) Why was the person unsuccessful?
Regular straw Modified straw
Straw Drinking RaceStraw Drinking Race1) Sucking creates a partial
vacuum or a lower pressurelower pressure in straw above the liquid that
we drink
2) The higher pressure in outside air pushes the
liquid up the straw in our mouth
The student with the modified straw cannot create a good vacuum (low pressure/no air) for very long
BECAUSE air from higher pressure outside comes in through the holes instead of pushing liquid up the straw