1What is an independent variable? Give one example.
2What is a dependent variable? Why can the experimenter not set its value directly?
3Why are controlled variables needed in an experiment?
4Identify the independent, dependent and controlled variables in an experiment on the effect of sunlight on plant growth.
5When studying the rate of reaction between the surface area of limestone and an acid, which variables must be controlled, and why?
6Name the type of each variable in the equation \( s = vt \). Why is s written on the left?
7On which axes are the dependent and independent variables plotted on a graph? What other names do they get because of this?
8In the catapult experiment, a student stretched the band further on her second trial and also switched to a thicker band. The bullet went much further. What went wrong with her experiment?
9In an investigation of the effect of heat on the solubility of sugar, why is the water always kept at 100 grams? Also name the independent and dependent variables.