1. VARIABLES

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

3. 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

4. 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

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

6. 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.

7. 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.