What you are deliberately changing, e.g. temperature
Dependent variable
What you are measuring, e.g. a rate of a reaction
Control variables
The other factors which might affect the dependent variable, including both biological factors (e.g. species, age, fitness) and non-living factors (e.g. concentrations of solutions, temperature, and pH)
Designing experiments
1. Identify independent variable
2. Identify dependent variable
3. Identify control variables
4. Plan to repeat experiment for each value of independent variable
