Station 1
Balloon over a Bottle
Illustrated Concepts
Gases expand, or take up more space,
when they are heated. As a gas
becomes warmer, its molecules move
further apart.
What You Need
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1 plastic 2-liter bottle
1 large bowl or pan
1 balloon
Water
What To Do
1.
2.
3.
4.
5.
6.
Fill the bottle with cold water.
Fill the pan with hot water.
Empty the cold water out of the bottle, and then pull the balloon over its mouth.
Set the bottle in the pan of hot water.
Observe what happens when the cold air inside the bottle becomes warm.
Clean up. Use caution when handling the hot water and bowl.
What's Happening
Most things expand when they are heated and contract when they are cooled. This occurs with solids and
liquids, but it is most noticeable with gases. The cold water cools the plastic bottle, and after the water is poured
out, the cold bottle cools the air inside it. When the bottle is placed in hot water, the air inside it warms and
expands. The molecules that make up the air inside the bottle move apart and take up more space. When the air
takes up more room than the bottle can hold, it inflates the balloon.
What does this activity tell you about the density and volume of warm air and that of cold air?
http://www.mdsci.org/science-encounters/Demo/BalloonBottle.html
Station 2
Cloud in a Bottle Demonstration
Use Smoke to Form a Cloud
By Anne Marie Helmenstine, Ph.D., About.com Guide
You can make your own cloud in a bottle using a bottle, some warm water, and a match.
Here's a quick and easy science project you can do: make a cloud inside a bottle.
Clouds form when water vapor forms tiny visible droplets. This results from cooling the
vapor. It helps to provide particles around which the water can liquefy. In this project,
we'll use smoke to help form a cloud.
Cloud in a Bottle Materials
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1-liter bottle
warm water
candle and match
Let's Make Clouds
1.
2.
3.
4.
5.
Pour just enough warm water in the bottle to cover the bottom of the container.
Light the match and place the match head inside the bottle.
Allow the bottle to fill with smoke.
Cap the bottle.
Squeeze the bottle really hard a few times. When you release the bottle, you should see the cloud form. It may
disappear between 'squeezes'.
The Other Way to Do It
Ok, here's the ideal gas law:
PV = nRT, where P is pressure, V is volume, n is number of moles, R is a constant, and T is temperature.
If we're not changing the amount of gas (as in a closed container) then if you raise the pressure, the only way for the
temperature of the gas to be unchanged is by decreasing the container volume proportionally. I wasn't sure I could
squeeze the bottle hard enough to achieve this (or that it would bounce back) and I wanted a really dense cloud for
the photograph so I did the not-as-child-friendly version of this demonstration (still pretty safe). I poured water from
my coffeemaker into the bottom of the bottle. Instant cloud! (... and a slight melting of the plastic) I couldn't find any
matches, so I lit a strip of cardboard on fire, inserted it into the bottle, and let the bottle get nice and smoky (and
melted more plastic... you can see the deformation in the photo). Dense cloud, no squeezing required, though of
course it still worked.
How Clouds Form
Molecules of water vapor will bounce around like molecules of other gases unless you give them a reason to stick
together. Cooling the vapor slows the molecules down, so they have less kinetic energy and more time to interact with
each other. How do you cool the vapor? When you squeeze the bottle, you compress the gas and increase its
temperature. Releasing the container lets the gas expand, which causes its temperature to go down. Real clouds form
as warm air rises. As air gets higher, its pressure is reduced. The air expands, which causes it to cool. As it cools
below the dew point, water vapor forms the droplets we see as clouds. Smoke acts the same in the atmosphere as it
does in the bottle. Other nucleation particles include dust, pollution, dirt, and even bacteria.
Station 3
Cloud in a Jar
In this activity you will model cloud formation in a jar.
Materials
 Ice cubes
 Warm water
 Jar
 Tray or pie pan
Procedure
1.
2.
3.
4.
Pour a small amount of hot water into the bottom of the jar (about 4 cm)
Fill the tray with ice cubes.
Set the tray on top of the jar’s opening. Wait and observe.
Clean up.
Station 4
Stubborn Paper Wad
E. Richard Churchill, Louis V. Loeschnig, Muriel Mandell, and Frances Zweifel: 365
Simple Science Experiments with Everyday Materials (1997), page 137.
Objective: To learn more about air pressure and its properties.
Standards: Structure of the Earth System (atmospheric composition and properties at different elevations), and
Motions and Forces (laws of motion).
Procedure:
Materials: A small – mouthed bottle and a small piece of scrap paper.
Steps:
(1) Place the bottle on its side on a table.
(2) Form a small wad with the scrap paper that is approximately the size of a pea.
(3) Place the paper wad just inside the bottle’s mouth.
(4) Blow hard and fast into the bottle.
Science Behind It: The paper wad should fly out of the bottle back towards the person who blew at it (adjust
wad placement and degree of blowing if this does not result). This occurs because the rapid moving air goes
past the wad and strikes the bottom and sides of the bottle. As a result, this increases the air pressure inside the
bottle and as this air suddenly rushes out of the bottle to equalize air pressure, it pushes the wad out with it as
well.
STATION 5
Air Has Mass
Purpose: Demonstrate that gases have mass just like other substances.
Materials:
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Goggles
Erlenmeyer Flask (Glass with large bottom and skinny top)
Graduated cylinder
Clear Plastic Bin
Candle
Lighter
Baking soda
Vinegar
Teaspoon
Procedure:
1.
2.
3.
4.
5.
6.
7.
8.
Measure 40-mL of vinegar in the GRADUATED CYLINDER.
Put 5 mL of baking soda in the bottom of the Erlenmeyer flask.
Set the candle in the clear plastic bin.
WEARING GOGGLES pour the vinegar on top of the baking soda and allow to react completely
(fizzing should be mostly stopped).
Light the candle.
In your flask you should now have carbon dioxide gas and water.
Very carefully pick up the Erlenmeyer flask and pour JUST THE GAS around the lit candle. Make
sure not to pour any of the water. Observe!
CLEAN UP:
a. Empty and rinse the flask.
b. Wipe off the countertop!
The Erlenmeyer flask is VERY fragile and quite expensive ($9). If you
break it, I will put your name on the school fine list to replace it  Handle
very carefully and turn water on LOW BEFORE placing the flask under the
faucet to rinse!
Analysis Questions for Lab B: (Answer on your own sheet of paper)
1. What happened to the candle when you poured the CO2 gas on it?
2. How did this experiment demonstrate that gases have mass?
3. What did this experiment tell you about the mass of CO2 gas compared mass to the primary gases
of our atmosphere: nitrogen (N) and oxygen (O2)?
4. Carbon dioxide acted like ______________________ (cold or warm) sinking air, forming wind.
5. Conclusion: I learned THAT…
STATION 6
The Collapsing Can
We are so accustomed to the pressure of the air around us that we don't even notice it. However, the air pressure
is large enough to crush a soda can. You can see the air crush a can in this experiment.
For this experiment you will need:
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an empty aluminum soft-drink can
a 2- or 3-liter (2- or 3-quart) saucepan
a pair of kitchen tongs
a heat source like hot plate
o Fill the saucepan with cold tap water.
o Put 15 milliliters (1 tablespoon) of water into the empty soft-drink can.
o Heat the can on the hot plate to boil the water. When the water boils, a cloud of condensed vapor will
escape from the opening in the can. Allow the water to boil for about 30 seconds.
o Using the tongs, grasp the can and quickly invert it and dip it into the water in the pan.
o Record what happens.
The can will collapse almost instantaneously. What caused the can to collapse? When you heated the can you
caused the water in it to boil. The vapor from the boiling water pushed air out of the can. When the can was
filled with water vapor, you cooled it suddenly by inverting it in water. Cooling the can caused the water vapor
in the can to condense, creating a partial vacuum. The extremely low pressure of the partial vacuum inside the
can made it possible for the pressure of the air outside the can to crush it.
A can is crushed when the pressure outside is greater than the pressure inside, and the pressure difference is
greater than the can is able to withstand. You can crush an open aluminum can with your hand. When you
squeeze on the can, the pressure outside becomes greater than the pressure inside. If you squeeze hard enough
the can collapses. Usually, the air pressure inside an open can is the same as the pressure outside. However, in
this experiment, the air was driven out of the can and replaced by water vapor. When the water vapor
condensed, the pressure inside the can became much less than the air pressure outside. Then the air outside
crushed the can.
When the water vapor inside the can condensed, the can was empty. You may have expected the water in the
pan to fill the can through the hole in the can. Some water from the pan may do this. However, the water cannot
flow into the can fast enough to fill the can before the air outside crushes it.
CAUTION: Do not heat the can over high heat or heat the can when it is empty. This may cause the ink
on the can to burn or the aluminum to melt.
STATION 7
Candle Under a Jar
Materials- goggles, small jar, larger jar, pie pan, candle, clay, oven mitt
Steps
1.
Put on goggles
2.
Carefully light the candle.
3.
Hold a small glass jar by the bottom. Lower the mouth of the jar over the candle until the jar
rests on the pie pan. As you do this, start a stopwatch or note where the second hand is on
the clock.
4.
Watch the candle carefully. How long does the flame burn?
5.
Using tongs or an oven mitt, remove the jar. Relight the candle and then repeat using the
larger jar.
6.
Using tongs or an oven mitt, remove the jar and relight the candle. Now hold the bottom of
the glass jar just above the candle flame. What happens to the bottom of the jar?
Combustion:
candle wick + oxygen -----> carbon dioxide + water + heat
Wick + O2 ----> CO2 + H2O + heat
STATION 8
Removing Air Lab
Purpose: Model what happens when air is removed.
Materials:
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Vacuum pump
Bell jar
Balloon
Small candle
Other materials ???
Procedure:
1. Mrs. McNees is the only one allowed to use the
machine.
Analysis Questions to answer for Lab A: (on your own
sheet of paper)
1. What happened to the balloon (or other object) when air was removed from the bell jar?
2. How did this experiment demonstrate that air can be removed?
3. Conclusion: Describe what you learned.