Daniel Harris
January 17, 2010
Carbon Dioxide Experiment
Hypothesis:
In this experiment we expected that when we blew into the straw that the color of
the bottle would change. Our hypothesis was that if we blew into the flask that then the
color of it would change. The independent variable in this experiment was the physical
activity of us blowing into the straws. The dependant variable in this experiment was the
amount of carbon dioxide.
Procedure:
First we took a flask and put 75ml of water in it and then added 20 drops of
bromothymol blue and stirred it. We then took a straw and blew into the flask. Once we
exhaled enough carbon dioxide the solution turned from blue to green. To get the solution
back to blue and kept adding drops and stirring until it was back to normal. We wanted to
see what would happen if we did some sort of physical activity and then try blowing into
the solution again. We found that it was harder to change the color of the solution once
you had a higher heart rate. We did these steps twice and got the same result. The
controlled variable in this experiment was when we blew into the solution without any
physical activity. The standardized variables in this experiment were that there were two
males and two females.
Data:
Carbion Dioxide Experiment
Abi Keeley Roger Dan Average
No physical
Activity(amount
of drops)
13 8 23 20 16
Physical
Activity(amount
of drops)
20 16 27 30 23.25
With no physical activity we found that it took less drops than with physical activity.
Conclusion:
We found that our hypothesis, if we blew into the flask that the color would
change, was true. Our data supports our hypothesis because we found that the more we
blew into it the more the color would change.
