IF YOU'RE UNDER PRESSURE, BLAME IT ON THE AIR FORCE
Air is all around us, and is necessary for our survival on earth.
This lesson allows the students to investigate the idea that air is not
just something that we breathe, but a powerful force that is all around
us. The students will learn that air is pushing constantly in every direction;
up, down, and sideways. They will also learn that air can do work. This
activity allows the students to do experiments, collect data, make charts
and graphs, and interpret their findings.
Science For You #6: How Heavy Is Air?
The Science Alliance #7: Air
Take a Look 2 #1: Air Pressure
Students will be able to:
- demonstrate that air exerts a force
- define air pressure
- construct a siphon
- estimate the time it will take to siphon different amounts water;
and collect, chart, and analyze data
Can Crushing Demonstration:
Siphon Activity Per group or four students:
- 1 aquarium or other large container
- 6 empty soda cans
- ice cold water (enough to fill aquarium)
- 1 pair tongs
- 1 hot plate
Note: both bottles should have markings of 1/4L, 1/2L, 3/4L, and 1L 1 piece
plastic tubing (1/4 inch by 4 feet)
- 1 one-liter bottle (empty)
- 1 one-liter bottle (filled with water)
- 1 piece plastic tubing (1/8 inch by 4 feet)
- 1 stopwatch
Place about one-half inch of water into an empty soda can. Tell
the students to observe the can. Put the can on the hot plate and heat it
until you see steam coming out of it. Ask the students what they observe.
Elicit responses. Using tongs, grasp the can, quickly invert the can,
and put it into the cold water. (The can should be as vertical as possible
and placed into the cold water about one half of an inch deep.) The students
will hear and see the can crush. This activity dramatically shows the students
how powerful the air is, and should be repeated a couple of times. Ask the
students why the can was crushed when it was placed in the cold water. Elicit
The focus for viewing is a specific responsibility or task(s)
students are responsible for during or after watching the video to focus
and engage students' viewing attention. Tell the students that they are
going to view three video segments that will help them understand why the
Tell them that in the first segment they will watch a similar can crushing
experiment, and that they should be able to answer the following questions:
What happens to the air in the can as it is being heated? What evidence
did you see? Does air have weight? How much weight does it exert? Why did
the can crush?
In the second segment, the students will watch an experiment, first without
sound and then with sound. Tell the students that they are to determine
why the water doesn't come out of the glass jar. Inform the students that
the first two segments will help them apply their knowledge of air pressure
in a different situation. When they finish watching the third segment, they
should be able to explain what a siphon is and how it works.
BEGIN the video Science for You #6: How Heavy Is Air?
when you see a can on its side with the words "Experiment: Air Has
Pressure." PAUSE when you first see steam coming out of the
can. Have the students describe the similarities between what they saw in
the video and what they saw in the earlier demonstration. Elicit responses.
RESUME the video and PAUSE when the can is put into the water.
Ask the students if they know what is going to happen to the can and why.
RESUME the video and PAUSE when three yellow arrows are drawn
around the can. Ask the students if they think more arrows should be drawn
to help explain what is happening. With a water soluble marker, have a volunteer
draw three more arrows on the television screen. Ask them what the arrows
represent. Discuss how they represent the air pushing in all directions.
Erase the arrows from the television.
RESUME the video and STOP when you see a map of the earth
and the narrator says "That's pretty heavy." Ask the students
how much weight air exerts. Discuss responses. Review how the can was crushed
by the air.
BEGIN the video The Science Alliance #7: Air when you see
a lady holding a green ball saying "I'm pressing on a foam ball."
PAUSE the video when she turns a flask upside down, holding a note
card to the opening. Ask the students what they think will happen when she
moves her hand away from the note card. Elicit responses.
RESUME the video and STOP when she pulls the note card from
the opening and lets the water out. Ask the following questions. Did the
card fall off when the flask was upside down? When it was sideways? Why
didn't it fall off? Elicit responses and discuss.
BEGIN the video Take A Look 2 #1: Air Pressure when Kate and
Jeff are sitting at a table and Kate says "Now let's go to my workshop
and I'll show you a way to move water around where you don't have to use
so much energy." PAUSE the video when Kate and Jeff are in the
workshop and she says,"This is a siphon." Ask if anyone knows
what a siphon is, and if anyone has used a siphon. Elicit responses and
RESUME the video and STOP when Kate says, "And letting
air pressure do the work for you." Ask the following questions: What
work was being done? What did the work? Who can explain what a siphon is
and how it works?
In the last video, the students saw how a siphon is made and
how it works. The assignment is to make a working siphon and calculate how
long it takes for the water to move from one bottle to the other. The experiment
will be done twice. First, the students will use the 1/8" by 4' piece
of tubing to determine how long it takes to fill the bottle on the floor
1/4 full, 1/2 full, 3/4 full and 1 full liter. Then, the students will repeat
the experiment using the 1/4" by 4' piece of tubing.
Note: Make estimates before doing the actual timings. Take some time to
"play around" with the siphons to make sure that you understand
how they work. Once you feel comfortable with your siphon, do the experiment
and fill out the worksheet.
Have a local farmer visit the class to discuss how he uses siphons
to irrigate his fields.
Invite a city engineer to class to discuss how the water systems and sewage
treatment plants work.
Have a plumber visit the class and discuss how plumbing in your homes work.
He can also bring in various pumps to show the class.
Invite a meteorologist to class to discuss how air pressure is related to
our daily weather.
Visit a gardening store that sells pumps for garden ponds.
Social Studies and English: Have the students research and write
papers on ancient civilizations and how people irrigated their farmland.
Science and Art: Using battery-operated pumps, have the students make their
own miniature water gardens.
Science and English: Have the students build a model of a reservoir and
make class presentations with them.
Science and Math: Using small electric pumps (like those used to drain waterbeds),
have the students calculate the number of gallons each pump circulates in
a minute, for every ten minutes, per hour.
Math: Have a contest where the students have to figure out how long it will
take to drain an aquarium using different amounts and different sized tubing.
Click here to view the
worksheet associated with this lesson.
Master Teachers: Michael Adorjan and Nadine Risley
Lesson Plan Database
Thirteen Ed Online