Variables

• Independent variable– Usually the “If” part of your hypothesis– What you test or change in your investigation– Found on the X-axis

• Dependent variable– Usually then “Then” part of your hypothesis– What you are measuring– Found on the y-axis

How does the intensity of the sunlight affect pine tree height?

Independent and Dependent Variables

How does the amount of sugar affect the thickness of ketchup?

How does the type of liquid poured on limestone affect the limestone’s texture?

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Independent and Dependent Variables If you roll a heavier steel ball off an

inclined ramp, then it will travel further than a light steel ball, because the heavier ball has more momentum.

Independent Variable –Weight of ball

Dependent Variable –Distance ball travels

Independent and Dependent Variables If the particles in a tube are small, then

water will pass through the tube more slowly than if the particles are large, because there is less space between the particles. Independent Variable –

Size of particles

Dependent Variable –Speed water passes

A botanist conducted an experiment to see how a new fertilizer affects plant growth. He set up 100 plants and added fertilizer 3x a week. He set up another 100 plants and did not add fertilizer at all. He then measured and recorded each plant’s growth for 2 months.

Independent and Dependent Variables

Independent Variable –

New fertilizer

Dependent Variable –

Plant growth

If you increase the size of a sponge, then it will absorb more liquid, because it has more surface area.

Independent and Dependent Variables

How does a person’s height affect their lung capacity?

How does the rate at which kool aid dissolves in water depend on the water’s temperature?

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