Science Buddies: "Ask an Expert"

Hi,
My daughter chose the 'Leaky Clues To Dam Design' project for the science fair this week. We are trying to figure out what the independent, dependent and controlled variables are. Here is what we think:

Independent variable: Opening of the holes by removing the duct tape
Dependent variable: Height of water and stream length
Controlled variable: Holes position

Could you please let us know if this is correct? Thanks.

Certainly whether you remove the tape or not will influence the result, but maybe there's more. How are the holes placed? When you poked the holes in the bottle, how might the results have been different if you used more or fewer holes, or if you placed them in different positions?

The independent variable is what you manipulated which influenced the results you got - in general, it's what you're curious about and what you're trying to test. What did you have control over when you set up the experiment that determined how the water came out?

The dependent variable then is what you measured and the control variables are things you would keep the same between trials if you did it repeatedly and changed the independent variable. One is the size of the water bottle and how far you filled it up before removing the tape. Another might be the hole size if you always used the same nail. Is there anything else you can think of that stayed the same?

Howard

Thank You so much for taking the time and explaining it so clearly. We really appreciate it.