Examples of Variables Independent Variable Dependent Variables Controlled Variables Question (What I change) (What I observe) (What I keep the same) The faucet pressure, or how much the water is "pushing" How much water Water faucet opening Amount of water flowing, "Different water pressure might also cause different flows through a faucet (closed, half open, fully measured in liters per amounts of water to flow and different faucets may behave at different openings? open) minute differently, so to ensure a fair test, I want to keep the water pressure and the faucet the same for each faucet opening that I test." Stirring Type of Does heating Temperature of the Amount of sugar that allow it to dissolve water measured in dissolves completely, "More stirring might also increase the amount of sugar that more sugar? degrees Celsius measured in grams dissolves, and different sugars might dissolve in different amounts, so to ensure a fair test I want to keep these variables the same for each cup of water." Growth of the plant, measured by Same type of fertilizer its height Same pot size for each Does fertilizer make a Amount of fertilizer, Growth of the Same plant type in each pot plant grow bigger? measured in grams plant, measured by Same type and amount of soil in each pot the number of Same amount of and light leaves
Examples of Variables Question Independent Variable (What I change) Dependent Variables (What I observe) Controlled Variables (What I keep the same) How much water flows through a faucet at different openings? Water faucet opening (closed, half open, fully open) Amount of water flowing, measured in liters per minute The faucet pressure, or how much the water is "pushing" "Different water pressure might also cause different amounts of water to flow and different faucets may behave differently, so to ensure a fair test, I want to keep the water pressure and the faucet the same for each faucet opening that I test." Does heating allow it to dissolve more sugar? Temperature of the water measured in degrees Celsius Amount of sugar that dissolves completely, measured in grams Stirring Type of "More stirring might also increase the amount of sugar that dissolves, and different sugars might dissolve in different amounts, so to ensure a fair test I want to keep these variables the same for each cup of water." Does fertilizer make a plant grow bigger? Amount of fertilizer, measured in grams Growth of the plant, measured by its height Growth of the plant, measured by the number of leaves Same type of fertilizer Same pot size for each Same plant type in each pot Same type and amount of soil in each pot Same amount of and light
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