Science Buddies: "Ask an Expert"

Hi -- for the experiment about what kind of bridge holds more weight (building a suspension bridge and a beam bridge), what is the independent variable? Is the kind of bridge the independent variable since we're changing it, or is the number of pennies put into the weight cup the variable that changes?

Hi! Sounds like a fun experiment.

In general, the independent variable is controlled entirely by the experimenter, while the dependent variable depends on the independent variable. The dependent variable is what you actually measure.

In your experiment, you pick a few types of bridge, and you measure the number pennies that can be added before the bridge collapses. Think about it this way- does the type of bridge depend on the number of pennies added before collapse or does the number of pennies added before collapse depend on the type of bridge?

Hope that helps!
Megan