Smelly BalloonsDiffusion Activity

Materials• 5 balloons of different colors• Flavor extracts• 1 Pipet for each extract

Pre-Lab Set-Up1. Select S balloons of different colors. Use a different colored balloon for each extract.2. Stretch each balloon several times with your hands before inflating. Inflate each balloon

completely and then let the air out.3. Using a pipet, add 2 mL of a flavor extract to each balloon. Insert the pipet tip well

inside the balloon before squeezing the extract into the balloon. To make this step easier,have one group member stretch the opening of the balloon while another group memberpipets the extract.

4. Note which extract is placed in each balloon. In your data table, record the color of eachballoon and the letter of the extract used in that balloon.

S. Blow up the balloons and tie them shut. Make sure that when you blow up the balloonyou do not tip the extract up into your mouth.

Procedure1. You will be placed in groups of 3-4.2. Record the start time for each balloon. The start time is recorded once you initially tie

the balloon after adding the extract.3. Pass the balloons around within the groups.4. Record the time at which you can begin to smell the extract FROM ABOUT AN ARM'S

LENGTH AWAY, as well as the flavor of the extract.S. Continue until the smell is no longer detected, and record that time.6. Repeat these steps for S different extracts.7. Record all results on your data table in your lab notebook, and make a bar graph of your

final results.

Data Table

Balloon Extract Start Time Initial Extract Stop Time Total DiffusionColor Number (After Smell type/flavor (Time Time (total time

Balloon is Time Smell from start toTied Off) Ceased) stop)

Smelly Balloons Conclusion Questions:To be completed in your lab notebook

1. Compare your results with another group. What differences did you find in your results?

2. List two variables that could have been the cause for your differences

3. Why do you think we stretched the balloons before we added the extract and inflatedthem? Do you think that if we had not stretched the balloons we would have found adifference in our results? Explain.

4. Was this lab an example of diffusion or osmosis? How do you know?

5. Was any energy required in order for the extract to diffuse through the balloon? Whattype of transport was represented in this lab?

6. Compare the balloon to the selectively permeable membrane that contains our cells. Howare the two alike? How are they different?