The air of your ways

(Balloon in a Bottle) 

Material:

2 empty 1 liter plastic bottles (20 oz soda bottles work great)

2 balloons

a nail and a pair of pliers

  

 

 

 

Film and activity updated by

Heather West

Procedure:

Clean and dry the two empty one liter soft drink bottles. Hold the nail with the pliers and heat it over the stove. Then carefully punch a small hole, (1/8th" or less), in the side wall of one of the bottles, approximately two inches from the bottom. Do not make a hole in the other bottle. Lastly, make sure that the balloons used will easily attach to the bottle top.

 

Presentation:

1. Select a "Windy" student helper. challenge the student to make careful observations and imitate your exact motions. Ask the student to identify the contents of the "empty" bottle. Do not refer to the presence of air at this point, if it is not mentioned.

2. As the student to mimic your motions. The example, repeatedly stretch the balloon in several directions to make it flexible.

3. Insert the uninflated balloon into the bottle, and attach the balloon to the neck of the bottle. The teacher should have the bottle WITH the hole. Do not allow the student to see the small hole.

4. Hold the bottle so that one finger is lightly placed over the small hole. Blow into the bottle and inflate the balloon. As the balloon inflates, the teacher will feel air escaping from the small hole. When the balloon is inflated, press your finger over the hole and the balloon will remain inflated within the bottle.

5. The student will not be able to inflate the balloon in the hole-less bottle.

6. Ask for possible explanations for both your success and the students difficulty.

7. To make the drama even more visual, the teacher may wish to place a pencil in the open balloon or even full the balloon with water.

8. At just the right moment, a slight movement of the finger will allow for a messy follow-up discussion.

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