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

Q5lc&feature=related

• Make diagrams of push and pull

Syringe Activity- How does air move?

1) With the tube clamped shut, push on the plunger then release the clamp.

-Which way does the air move? Why?

2) Put the clip back on, pull on the plunger then release the clamp.

-Which way does the air move? Why?

3) Draw diagrams.

Cause of Air Movement

• Need to think about air pressure in one place compared to it’s surroundings– Ex) Sisters – 1 person alone is not cause, it’s

relationship between both of them– Can make comparisons- 1 is older than other

• High pressure moves to low pressure

Challenge:

Results and Explanation:

1. Fill a cup with water. 2. Cover the cup with an index card.

3. Invert the cup. What happened?

Does the water spill out of the cup? Explain (using concepts on pressure)

PRESSURE CIRCUS Activity 1. Inverted Cup

Summary:

Inverted CupInverted Cup

cardboard

High Air Pressure

Why is it low air pressure inside the cup?

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

Collapsing CanCollapsing Can

- the can was filled with water and air.

-boiling the water steam pushed the air out of the can (LESS AIR PARTICLES).

- turn can upside down to block the hole in can air can’t go in or out

Lower pressure inside so higher pressure outside 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

Challenge:

Results and Explanation:

Who can drink the fastest?

Title: Activity 3: Straw drinking race Date: Feb. 2010

Summary:

1) Who was successful and who wasn’t?

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

Challenge:

Solution:

Results and Explanation:

How can you stop the leak in this soda can?

Title: Activity 4 Stop the Leak Date: Feb. 2010

Summary:

DID NOT DOTHIS ONE

Stop the LeakStop the LeakBy plugging one of the holes, the air inside stays the same because

outside air is prevented from coming into the hole. The higher

water volume inside causes a decrease in pressure. Thus, outside air pressure (which is

greater) pushes against the water and prevents it from flowing out.

Air cannot go in

Liquid cannot

flow out

Air pressure outside of can is Air pressure outside of can is greater than air pressure inside.greater than air pressure inside.