Balloons In Science

Ilene Wagner                   O. A. Thorp Scholastic Academy
                               6024 W. Warwick
                               Chicago IL 60634
                               (312) 534-3640                                   

Celestine Jeffreys             Hales Franciscan H.S.

Objective:

     The main objective of this mini-teach is to suggest various ways for 
teachers to use balloons to teach science concepts such as air pressure, static 
electricity, etc. 
     BALLOONS HAVE MANY USES IN THE SCIENCE CLASSROOM.  THEY CAN BE THE LID ON 
AN EXPERIMENT, SHOW EXPANSION AND CONTRACTION, MASS, MOVEMENT, INERTIA, AIR 
PRESSURE, HOW YOUR BODY WORKS, STATIC ELECTRICITY, AND MANY OTHER CONCEPTS.  
I'LL TRY TO SHOW YOU HOW TO USE THEM EASILY. 
     THERE ARE MANY TYPES OF BALLOONS:  ROUND, LONG & SKINNY, SMALL & LARGE, 
HEAVY & LIGHT, RUBBER & MYLAR.  TRY TO HAVE AS MANY ON HAND AS YOU CAN TO 
DEMONSTRATE VARIOUS CONCEPTS AND HAVE YOUR STUDENTS PARTICIPATE IN THE LABS.  
     TEMPORARY CLOSURES INCLUDE: MARBLES, TWIST-TIES, RUBBER-BANDS, SNAP CLOTHES 
PINS, AND STRING. 

          1. Put some type of perfume into a thin balloon and blow it up.  Use 
this with other odors.  Let students compare the smells.  It can also be used to 
show how molecules can diffuse through what seems to be a solid surface. 
          2. Make a frame using two boards about 10" X 4" X 1/2" connected by a 
hinge.  Use eye hooks or thumb tacks to attach a string tied to the ends of the 
balloons.  This will show how the muscles (balloons) and tendons (string) 
stretch and contract when you bend your arm.  Use lines on the balloons to show 
the way in which they stretch. 
          3. Use the top half of a 2 liter pop bottle to show how the lungs 
expand and contract during respiration (breathing) using the diaphragm.  Put a 
"Y-tube" or a straw into a large one-hole stopper or a piece of clay.   Put a 
small balloon on the end of the straw or both ends of the "Y-tube" using rubber 
bands to keep in place.  Place the clay around the straw to prevent the air from 
escaping from the bottle, or use the stopper.  Cut the neck off a 16" balloon, 
place the balloon over the bottom of the pop bottle.  Use the rubber-band to 
keep the balloon in place over the bottom of the top half of the bottle.  Pull 
gently on the large balloon and watch what happens.  (1) What do you observe?  
(2) How do you explain it?  Increasing the pressure by pulling the diaphragm 
increases the volume of the air in the lung balloons. 
          4. Tie and tape a piece of yarn or string to the center of a straw, 
dowel rod, or cardboard cleaner's hanger tube.  Attach two identical balloons 
with clothes pins, clips, or pins to the ends of the rod.  Be sure to make them 
balance.   Take off one of the balloons and inflate it fully.  Then tie it off 
and reattach it to the rod.  (1) When the inflated one is attached,  what 
happened to the balance?  (2) Can you explain why it occurred?  Air has mass.  
The air makes the balloon bring the balance arm down. 
          5. Inflate two identical balloons to about the same size.  Tie a 
string about 30 cm long to each.  Hold them about 3 cm from each other and blow 
through the space between them. (1) What occurred? (2) What do you think 
created that effect?  Blowing causes the air pressure between the balloons to 
decrease creating a need for the space to be filled and the pressure of the air 
on the outside of the balloons pushed them together. 
          6. Use two identical balloons.  Inflate one completely.  Use a snap 
clothes pin to close it, leaving some room at the neck end.  Inflate the other 
to one quarter the size of the first and use another clothes pin to close it in 
the same way.  Slip the end of the big balloon over a single-hold thread spool.  
Do the same with the other balloon at the other end of the spool.  Then, at the 
same time, take off both clothes pins of both balloons.  (1) What occurred?  (2) 
Why do you think that happened?  There is more pressure on the smaller balloon 
so the air goes into the bigger one. 
          7.   Write on a balloon with a felt marker and then blow the balloon 
up.  If you use a marble to block the stem, you can continue to increase the 
volume of air in increments instead of tying it off each time you what the class 
to view it.  This can be used to show how solar system, galaxies, constellations, 
and the universe are expanding.
          8. Inflate a balloon into a cup about a third at a time.  See what 
happens.  Try to pull it out.  (1) What is keeping it there?  (2) Why do you 
think this occured?  How do you release the balloon?  This is like a suction 
cup.  The air is forced out of the cup leaving little air.  The air from outside 
the cup and inside the balloon is holding the balloon in place.  To release, 
push the balloon to one side and allow some air to get into the cup. 
          9.  Fill a balloon.  Tie it off.  Using a sharp needle, gently pierce 
the balloon at the bottom end. (1) What did you anticipate occurring?  (2) What 
occured? (3) Why didn't it pop? The sharp needle pushed aside the rubber and 
quickly came around the needle. There is a greater amount of rubber at the end 
where the balloon is formed. 
          10. Assemble a straw, three meters of thin string, a long balloon, a 
clothes pin or marble, and a chair or door knob.  Put the string through the 
straw, blow up the balloon and clip or put a marble in the neck, tape the straw 
parallel to the neck on the balloon. Tie the string to something.  Let the 
students decide which way the stem of the balloon should face to make this 
rocket travel.  Have someone at the other end of the string catch the balloon. 
(1) What are some variables that can make this an experiment?  (2) Which way 
should you have the stem of the balloon? (3) What other vehicle is like this?  
The shape of the balloon could be a variable as well as the length of the 
string.  The length of string limits how far it can travel without stopping.  
The stem of the balloon should be facing the attached end of the string.  This 
could be likened to a monorail. 
               11. Get a 250ml Pyrex flask.  This is the safest.  Bottles that 
aren't Pyrex may be dangerous.  Put about 5 ml of water into the flask.  Heat on 
a hot plate until the water boils and fills flask with water vapor.  Get a 
helper to hold the flask with a potholder or clamp. Put a 9 inch balloon over 
the neck of the flask and place it on a table away from the heat.  (1) What did 
you observe?  (2) Why did this occur?  (3) How do you get the balloon out of the 
flask?  (4) What would happen if you didn't put water into the flask?  (5)  What 
if you put the flask into ice water?  (6) What if you put the flask into hot 
water?  The balloon will go into the flask because the water vapor replaces the 
air and the air is trying to get into the flask.  Heating the flask will create 
water vapor that will fill the balloon.  This will allow you to remove the 
balloon.  Be sure to do so before the water vapor cools again or the balloon 
becomes so large that it explodes.  Heating just the air will inflate the 
balloon.  Cooling the air will probably deflate the balloon but will not make it 
go into the flask. 
               12. Rub two inflated balloons on clean, dry hair. (1) What do 
they do when you try to put them together?  (2) What happens when you try to 
pick up some dry cereal, dots from paper punches, pepper, or other small items?  
You can use a balloon to make a soup can move in the same way.  Static 
electricity should repel the balloons just as magnets with the same negative 
poles repel each other.  Like charges repel.  The static electricity acts like a 
magnet on the small items because they are opposite charges.  Note: This works 
best in dry weather. 
               13. Carbon dioxide will fill balloons in many different 
ways. 1) Take yeast, sugar & warm water and put them in a flask.  Put a balloon 
over the flask and put the flask in a warm place for several hours to collect 
the gas.  2) Use various types of sodas to measure the amount of carbon dioxide 
in each.  3) Put baking soda into a balloon and some vinegar into the flask.  
Turn the balloon over to pour the baking soda into the flask and collect the 
carbon dioxide.  

Many of these activities can be varied to become a project for science fair.  
Choose variables that can be quantified so that it becomes an experiment and not 
a demonstration. 

Performance Assessment:

Each of the above activities is worth two points; one point for doing the 
activity correctly and one point for an explaination of the activity.

23-26 points = excellent
19-22 points = good 
15-18 points = fair
11-14 points = poor





This is adapted in part from other science activities and from Balloon Science 
Etta Kaner, Addison Wesley, 1989