VARIABLES

Testable Question What makes a question testable? It has variables It is something we can measure

Variables There are 3 kinds of variables in an experiment… Manipulated variable: The thing you change Responding variable: The thing you measure Controlled variable: The things that stay the same

Question: How much water flows through a faucet at different openings? Manipulated Variable Water faucet opening (closed, half open, fully open) Responding Variable Amount of water flowing measured in liters per minute

Controlled variables The Faucet Water pressure, or how much the water is "pushing"

Question: Does fertilizer make a plant grow bigger? Manipulated Variable Amount of fertilizer (measured in grams) Responding Variable Growth of the plant measured by its height Growth of the plant measured by the number of leaves Etc.

Controlled variables Same size pot for each plant Same type of plant in each pot Same type and amount of soil in each pot Same amount of water and light Make measurements of growth for each plant at the same time Keeping all of these things the same tells us that the only thing that could have caused differences in plant growth was the fertilizer.