Diffusion Through Balloons

Angela Patrick                 Crown Community Academy
Dorian Price                   Horatio May Academy
Elizabeth Abioro               Delano Elementary School

Objective:

To demonstrate the diffusion of gas molecules.

Materials Needed:

For teacher demonstration:     Per student group:
Blown-up balloons              8 unblown balloons
overhead (optional)            8 small plastic cups
transparency of                8 large plastic cups
  data sheet (optional)        8 eye droppers
prediction chart               data sheets

Items to test:
vanilla, coffee, milk, flour, sugar, lemon juice, vinegar, perfume.

Strategies:

Introduction:
Read the following poem to the students:  Balloons, Balloons, Balloons!
Everybody just loves balloons!  Balloons can take you up, high above the sky!
A big, big hot air balloon floating through the air.  Up and down, in and 
out, all without a care!  (A short story about balloons may be substituted.)

After the poem, throw out some balloons to the students.  Have them describe the 
balloons.  Write what they say on the overhead.  Ask:  "What kind of matter is 
it?"  (This question assumes that the students have already had some knowledge 
about matter, solids, liquids, gases.)  They will say that the balloon is a 
solid.  Ask: "Do you think anything can go through a solid material?"  On the 
prediction chart, record how many students said "yes" and "no". 

Hypothesis:  A substance can go through a solid.  Tell the students that they 
will experiment to find out whether or not a substance can go through a solid 
such as a balloon. 

1.  Apply two droppers of substances in the balloon.
2.  Blow up the balloon and tie it.
3.  Place balloon on cup and let it sit there for ten minutes.
4.  After ten minutes smell the cup.  Did the scent go into the cup?
5.  Complete the data sheet.

Performance Assessment:
    
    Teacher Observation

Note:  Set up a data sheet with four columns with the following headings:
       1) Substance
       2) Hypothesis
       3) Scented
       4) Unscented
Questions:
       1) Which scents went through the balloon?
       2) Which scents did not go through the balloon?
       3) Why do you think this happened?