Biology Experimental Design

Quantitative data

Quantity (Numbers/measurements)

Qualitative data

Quality (words/descriptions)

Control group

Acts as a comparison group; does not receive the independent variabl

Controlled variables (constants)

Factors kept constant in an experiment to ensure results are due to independent variable

Independent variable (IV)

The factor that is manipulated during the experiment (I change) by the experiment designer

Dependent variable (DV)

The factors that is measured or observed

If slices of potato are placed in salt solutions of increasing concentration, then the potato slices in higher salt concentrations will lose more mass. What is IV?

Salt concentration of solution

If slices of potato are placed in salt solutions of increasing concentration, then the potato slices in higher salt concentrations will lose more mass. What is DV?

Mass of potato slices (or loss of mass)

If slices of potato are placed in salt solutions of increasing concentration, then the potato slices in higher salt concentrations will lose more mass. What is the control?

Potato slides in 0% salt (distilled/pure water)

If slices of potato are placed in salt solutions of increasing concentration, then the potato slices in higher salt concentrations will lose more mass. What are some controlled variables?

potato variety, slice size, time left in solution, temperature kept, container used, etc.