1. Notes 1 SPI 0807.Inq.1 (Variables and Controls)
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Dependent Variables in Experiments
Used with the scientific method
Step 1: Ask A Question
Step 2: Form A Hypothesis
Step 3: Test The Hypothesis
Step 4: Analyze The Results
Step 5: Draw Conclusions
Step 6: Communicate Results
Step 7: Make Observations
Scientific Method
(In List Format)
Use dependent variables when you test your hypothesis by doing experiments 1

2. A Dependent Variable Notes 2 Types of Variables
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2 Types of Variables
Independent & Dependent
In an experiment…
…you should only test for ONE key thing at a time
When you repeat the experiment…
…only change this ONE key thing
This one thing is called…
ANYTHING ELSE THAT CHANGES IS CALLED…
An Independent Variable
A Dependent Variable 2

3. Dependent Variable Notes 3 SPI 0807.Inq.1 (Variables and Controls)
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So What Is A Dependent Variable?
Other factors that change because of the independent variable
These are the things that YOU DO NOT CHANGE…they change on their own
In other words, anything that changes on its own will be a…
Dependent Variable
Imagine you are doing an experiment to determine which brand
of gum will have flavor that lasts the longest.
The one thing you will change each time is the brand of gum
So the independent variable is the brand of gum
How long the flavor lasts will change on its own
So the dependent variable is how long the flavor lasts 3

4. Notes 4 SPI 0807.Inq.1 (Variables and Controls) Example 01
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Example 01
You decide to do an experiment to determine the reason certain soft drinks are more popular that other soft drinks. You suspect that the popularity of the drinks is connected with the amount of sugar found in them. You decide to use Coke, Pepsi, and Dr. Pepper in this experiment. You first determine how much sugar each drink contains. Then you get 6 students to do a blind taste test with all 3 drinks. They rate each drink on a scale of 1 to 10.
The independent variable is…
the type of soft drink
So what is the dependent variable?
HINT: What is a factor that changed without you doing it?
The dependent variable is the student’s rating 4

5. Notes 5 SPI 0807.Inq.1 (Variables and Controls)
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A scientist is conducting an experiment to test how
sunlight affects plant growth.
She places one corn plant 1 meter away from a sunlamp.
She places one corn plant 2 meters away from a sunlamp.
She places one corn plant 3 meters away from a sunlamp.
Example 02:
The independent variable is…
the amount of sunlight
So what is the dependent variable?
HINT: What is a factor that changed without you doing it?
The dependent variable is the plant growth 5

6. Notes 6 SPI 0807.Inq.1 (Variables and Controls)
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A student conducts an experiment with ten 8th grade students (5 boys and 5 girls). He uses 3 similar types of sour candy (Sour Skittles, Sour Patch Kids, and Warheads) in a series of 4 trials. He gives 1 piece of candy to each student and records their facial expressions as they eat it.
Example 03:
The independent variable is…
the type of sour candy
So what is the dependent variable?
HINT: What is a factor that changed without you doing it?
The dependent variable is the student’s facial reactions 6

7. Notes 7 SPI 0807.Inq.1 (Variables and Controls) Example 04:
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Example 04:
A student conducts an experiment to determine
which type of glue works best for attaching two pieces of regular
writing paper together.
He uses 3 types of Elmer’s glue in a series of experiments
(1) Liquid-washable, (2) Glue Stick-washable, (3) Glue Stick-nonwashable)
He places the same amount of glue (2g) on each sheet of paper.
The independent variable is…
the type of glue
So what is the dependent variable?
HINT: What is a factor that changed without you doing it?
The dependent variable is how strongly
the sheets of paper stick together 7

8. Notes SPI 0807.Inq.1 (Variables and Controls)
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SPI 0807.Inq.1
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Notes 
A student conducts an experiment to determine which
ink color in ballpoint pens will last the longest before running out.
She uses 3 ink colors in 3 ballpoint pens in a series of experiments.
(1) Black ink pen, (2) Blue ink pen, (3) Red ink pen)
She copies text from his science book. She copies the same text over
and over. She writes at the same speed. The room temperature
remains the same. She writes on the same kind of paper.
Example 05:
The independent variable is…
the ink color
So what is the dependent variable?
HINT: What is a factor that changed without you doing it?
The dependent variable is how long ink lasted 8