Science Buddies: "Ask an Expert"

I chose the science project How does drag effect the speed of a swimmer from Science Buddies and I'm trying to figure out my variables. Can you confirm the following: the controlled variable would be the time of day, the swimmer, the pool length, pool temp and stroke.
Dependent variable would be the time the swimmer gets across the 25m pool.
Independent variable would bet shirt and shorts v jammers and swim cap.

Could we change the experiment to see if adding fins and paddleswould improve the speed in the Tshirt and shorts or how could we further the experiment?

Thanks!

KDorsett,

Thank you for using the Science Buddies fora.

Your identification of the experiment's variables and constants look sound. However, I have one concern: one important constant is the swimmer's energy level. If you conduct the experiment in large portions, your swimmer might get tired! You need a way to isolate this unwanted variable (known by scientists as a confounding variable).

I like that you are interested in making the experiment more comprehensive. However, (at least in the science fair) it is generally unwise to add a second independent variable. You would have to perform twice as many trials for your experiment if you included fins and paddles than you would have to perform without this extra variable. Additionally, fins and paddles are more involved with propulsion than with drag.

Instead, I would suggest adding a different outfit. Try using long jeans, or a rain coat, or some other such garment.

I hope I have helped.


Good luck,
- Ultra