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Brian Cagle John W. Cook
8150 S. Bishop
Chicago IL 60620
The main objective of the mini-teach is to demonstrate an understanding of
how air pressure works. Students will be able to identify, construct, and
define the concept of air pressure by working in groups after experimenting
with various activities on air pressure. Students will also have a working
knowledge of the different terminology used when describing the process of air
Activity #1: Water Fountain
2 jars (one with the lid), 4 straws, small bucket, water, tape
Make two holes in the jar lid, one hole in the middle of the lid and the
other near the edge. Place one straw in the middle hole and secure both ends
of the hole with clay. Now tape the three straws together and place one end
inside the second hole of the jar lid about an inch. Secure both ends of this
hole with clay. Fill jar #1 without the lid about three-fourths of the way
with water. Now fill jar #2 with the lid about 2 inches high with water and
then close the lid. Take jar #2 with the lid and turn it over so that the
one straw in the middle hole is half-way in jar #1 and half-way in jar #2.
While the other straws which are connected are hanging over the edge into a
small bucket. Now observe what happens in jar #1 and jar #2.
As the water from the closed lid jar #2 pours down into the small bucket
through the connected straws, the air pressure inside the jar become less as
the air spreads out to take up space left by the water. The air outside in
jar #1 is at a greater pressure than the air inside, thus forcing the water up
the straw and making a fountain.
Activity #2: The Magic Glass
Jar, 4"x6" index card, water
Fill the jar to the top with water and wet the rim slightly. Lay the card
on the top of the jar. Hold the card firmly in place and turn the jar over.
Now take away your hand and see what happens.
The water should stay in the glass, showing that air pressure is exerted on
the card from the top, the side, and the bottom as Pascal's law states.
Activity #3: Candle In Glass
Shallow dish or pan, candle, matches, tall glass or flask, food coloring
Light a candle and stand it upright in the middle of a pan and secure it
with melted candle drippings. Fill the pan half full with water. Then add a
drop of food coloring to the water to make it more noticeable from the back of
the room. While the candle is still burning, place a narrow glass or flask
over the candle. Carefully observe the base of the container, the water level
in the container, and the flame. Record your observations.
The candle will burn for a time but will eventually go out and you will see
that the water rises up into the jar. You will find out that the water will
rise about one-fifth of the way up the jar. Water rises in the container due
to an imbalance in pressure. As the gas inside the container heats and expands
causing bubbling around the base. The oxygen inside diminishes, the flame gets
cooler, and so does the air resulting in a pressure drop. Water starts to move
into the container. When the candle is extinguished, the temperature in the
flask drops, causing a further reduction in pressure and a further rise in the
Activity #4: The Power of Air
Ruler, 2 sheets of notebook paper, 2 sheets of newspaper
Lay the ruler on the table so about one-third of it lies over the edge.
Place two sheets of notebook paper on the ruler and press against the table
until the paper is flat as possible. Now hit the overhanging portion of the
ruler with your hand and try to make the paper fly into the air. Repeat this
procedure using two sheets of unfolded newspaper and record your results.
The ruler should snap when placed under the newspaper, but not when placed
under the notebook paper. The notebook paper is small enough that the ruler
can lift it without breaking. While the newspaper has a much greater surface
area than the notebook paper. The air presses down on the sheet of newspaper,
there is a lot of air pushing down on it and this is enough to stop the paper
and ruler from moving.
Through an oral evaluation and teacher observations each student will have
to describe the procedure of each activity and the results of each experiment.
Explaining what happens when their is an indifference in air pressure and what
After experimenting with each activity, each student should have an
excellent idea of how air pressure works. While having a working knowledge
of some of the key terms associated with air pressure such as: high air
pressure, difference in pressure, and low air pressure.