Independent and dependent variables in my experiment

[Harwer8684]

Hi,
I would like to do use the experiment found here: http://www.scholastic.com/get_smart_abo ... riment.pdf for my science fair experiment. I have to take in a tri fold presentation for the fair.
What would the independent and dependent variables be?
Also, what about a hypothesis? Here are a couple of ideas we have come up with:
If you smoke then your lung tissue will become less elastic than a healthy lung because cigarette smoke hardens the alveoli making it difficult for them to expand and contract.
or
If an elastic, healthy lung and a less elastic lung due to cigarette smoking inhale air then the healthy lung will expand more than the unhealthy lung because of its loss of elasticity.
Thank you,
Buzz

[RicaC]

Dear Harwer8684,

In order to determine the independent variable, ask yourself "What am I changing in this experiment?"

In order to determine the dependent variable, ask yourself "What am I measuring in this experiment?"

Since this experiment was meant to model healthy and damaged lungs, your first part of hypothesis should focus on the experiment and save the concept that the experiment was trying to show you for the second part. It might help if you can identify the independent and dependent variables first before writing your hypothesis. Then, you could write your hypothesis more clearly in this format like this: If Independent Variable increases/decreases, then Dependent Variable increases/decreases because (for the reasoning, use the background information on what happens to the lungs when an individual smokes).

Please let me know if you want more feedback on your hypothesis or have any other questions.

RicaC