Control &amp; Variable Notes

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# Control &amp; Variable Notes - PowerPoint PPT Presentation

Control &amp; Variable Notes. Where do I start?. After you have a question that you want to answer using the scientific method, there are a few important things you need to think about while setting up your experiment. Example Question #1:.

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### Control & Variable Notes

Where do I start?
• After you have a question that you want to answer using the scientific method, there are a few important things you need to think about while setting up your experiment.
Example Question #1:
• Does heating a cup of water allow it to dissolve sugar faster?
THE CONTROL
• A control is the part of the experiment that remains the same.
• It may also be called the constant.
How to Remember:
• WHAT I KEEP THE SAME
Back to the Example
• Question #1: Does heating a cup of water allow it to dissolve sugar faster?
• Control #1: Type of water, Type of sugar, amount of water…
CONTROL GROUP
• The control group provides a baseline for comparison.
HOW TO REMEMBER:
• LEAVE OUT WHAT YOU ARE TESTING
Back to the Example:
• Question #1: Does heating a cup of water allow it to dissolve sugar faster?
• Control #1: Type of water, Type of sugar, amount of water…
• Control Group #1: Room temperature water
What is a Variable?
• A variable is the part of the experiment that changes. An experiment usually has two kinds of variables: independent and dependent.
INDEPENDENT VARIABLE
• The variable that is changed by the scientist.
• To insure a fair test, a good experiment has only ONE independent variable. As the scientist changes the independent variable, he or she observes what happens.
HOW TO REMEMBER:
• WHAT I CHANGE
Back to the Example
• Question #1: Does heating a cup of water allow it to dissolve sugar faster?
• Control #1: Type of water, Type of sugar, amount of water…
• Control Group #1: Room temperature water
• I.V. #1 : Temperature of the water
DEPENDENT VARIABLE
• The variable that is caused by the change the scientist made.
• The scientist focuses his or her observations on the dependent variable to see how it responds to the change made to the independent variable.
HOW TO REMEMBER:
• WHAT I OBSERVE
Back to the Example
• Question #1: Does heating a cup of water allow it to dissolve sugar faster?
• Control #1: Type of water, Type of sugar, amount of water…
• Control Group #1: Room temperature water
• I.V. #1 : Temperature of the water
• D.V. #1: How fast sugar dissolves
Example #2:
• Question #2: Does fertilizer make a plant grow bigger?
Example #2:
• Control(s):
• size of plant
• size of pot
• amount of soil
• type of soil
• amount of water
Example #2:
• Control Group:
• A plant with no fertilizer
Example #2:
• Independent Variable (What I Change):
• Amount of fertilizer
Example #2:
• Dependent Variable (What I Observe):
• Height of plant
Example #3:
• Question #3: What type of dish soap best removes spaghetti sauce stains from plates?
Example #3:
• Control(s):
• amount of sauce
• type of plate
• amount of dish soap
Example #3:
• Control Group:
• Using just water to wash
Example #3:
• Independent Variable (What I Change):
• type of dish soap
Example #3:
• Dependent Variable (What I Observe):
• Amount of sauce stain leftover.