1. Variables and Controls
Day 1

2. So Let’s Begin, Shall We?
What are variables and constants?

3. What is changed by the Independent Variable
What stays the same
What I change
Woke up on time
Hit the snooze button
Made it to school on time
Missed the bus
Bus came at the same time
Bus came at the same time

4. Variables and Controls
Day 2

5. Independent Variables

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

7. (Variables and Controls)
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
Experiments
In an experiment you should conduct multiple trials
How many? More is better!
Experiments should include independent variables, dependent variables, constants, and controls.

8. An Independent Variable
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
Independent Variables
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…
An Independent Variable
Also know as….the manipulated variable

9. The Independent Variable
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
Memory Trick
Independent variable begins with the letter “I”
So remember the letter “I.”
Imagine yourself doing the experiment., and ask yourself…
“What ONE thing will I change when repeating the experiment?”
That one thing will be…
The Independent Variable
Also know as….the manipulated variable

10. (Variables and Controls)
Video Review
SPI 0807.Inq.1
(Variables and Controls)
Science
Let's take a moment to watch and
discuss a video-song about this topic
Link: Variables Song by Mr. Edmonds

11. What is the independent (manipulated) variable in this example?
Example: You decide to do an experiment to determine the reason certain soft drinks are more popular that others. You suspect that the popularity of the drinks is connected with the amount of sugar found in them. You decide to use Dr. Pepper, Coke, Pepsi, and Barq's root beer. You first determine how much sugar each drink contains.
Then you get 6 students to do a blind taste test with all 4 drinks.
What is the independent (manipulated) variable in this example?
In other words, what is the one thing being tested for or changed?
The independent variable is the type of soft drink

12. Exit Ticket – SPI 0807.Inq.1 Independent Variables
A student designs an experiment to determine how surface type affects the amount of force needed to roll a ball 20 meters. What is the independent variable?
the lengths of the surfaces C. the type of surfaces used
the force needed to roll the ball D. the type of ball chosen

13. 2

14. amount of phosphorus used per plant. C. type of each plant used.
A student wants to test how the concentration of phosphorus in a fertilizer affects plant growth. In designing this experiment the independent variable would most likely be the...?
amount of phosphorus used per plant. C. type of each plant used.
height each plant grows after given fertilizer. D. type of phosphorus used.
Students want to determine which type of plant will best survive in a hot, dry environment. They place four different types of plants in identical pots, and put all of the plants by the same large window. They give each plant the same amount of water every day.
Which of these is the independent variable for the students’ experiment?
amount of water C. type of plant
health of plant D. amount of sunlight 3 4

15. Dependent Variables

16. (Variables and Controls) Also called "Responding Variable"
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
What Is A Dependent Variable?
Often called the "responding variable" because it is the response to the factor that was previously introduced
These are the results that you observe after you introduced the independent/manipulated variable
In other words, anything that "changes on its own" while the experimenter is observing it will be a…
Dependent Variable
Also called "Responding Variable"

17. Example: 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.
Corn plant 01
Corn plant 02
Corn plant 03
The independent variable is the distance from the sunlamp
What is a dependent variable in this example?
HINT: What is the response to the distance from the sunlamp?
A dependent variable is the plant growth

18. Example: A student conducts an experiment with ten 8th grade
students. He uses 3 similar types of sour candy in a series of four
trials. (Sour Patch Kids, Sour Skittles, and Warheads) He gives
1 piece of candy to each student and records their facial expressions
to estimate how sour each candy is.
The independent variable is the type of sour candy
What is a dependent variable in this example?
HINT: What is the response to the different types of candy?
A dependent variable is their reaction (facial expressions)

19. The independent variable is the type of glue
Example: A student conducts an experiment to determine
which type of glue works best for attaching two pieces of regular
writing paper together.
She places 2g of glue on each sheet of paper, and then uses a spring scale
to measure how much force it takes to pull the sheets apart.
She uses 3 types of Elmer’s glue in a series of experiments.
Liquid-washable
Glue Stick-washable
Glue Stick-nonwashable
The independent variable is the type of glue
What is the independent (manipulated) variable in this example?
In other words, what is the one thing being tested for or changed?
What is a dependent variable in this example?
HINT: What is the result from using the different types of glues?
Dependent variable-how much force to pull apart the paper

20. What is the independent (manipulated) variable in this example?
Example 05: A student conducts an experiment to determine which
ink color in ballpoint pens will last the longest before running out.
She copies text from her 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 each time.
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)
What is the independent (manipulated) variable in this example?
In other words, what is the one thing being tested for or changed?
The independent variable is the color of the ink
What is a dependent variable in this example?
HINT: What is a result from using the different color inks?
A dependent variable is how long the ink lasts.

21. Exit Ticket – SPI 0807.Inq.1 Dependent Variables
Mrs. Logan designs an experiment to determine how surface type affects how far a ball will roll across a variety of surfaces.
What is the dependent variable?
the lengths of the surfaces C. how far the ball rolls
the type of surface D. the type of ball chosen
The picture below illustrates an experiment designed by Mrs. Pope to test plant growth using potted green bean sprouts placed in front of a window.
Which of these is the dependent variable in this experimental design?
how tall each plant grows C. the height of each plant’s ceramic pot
different types of light sources D. the distance from the light source 2

22. 3 4

23. Controls

24. (Variables and Controls) What Are Control Experiments?
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
What Are Control Experiments?
An experiment to verify the results of another experiment
using the same conditions except for one factor or variable
An experiment separated from the main experiment where the independent variable being tested cannot influence the results.
Simply remove the independent variable entirely or replace it with a neutral independent variable.
Also called control groups

25. Experiment Notes Control Experiment (Fruity Pebbles Example)
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
(Fruity Pebbles Example)
Experiment
Does eating a sugary cereal make children hyperactive?
Every day for a week have 3 children eat a bowl of Fruity Pebbles.
Then observe their energy level for the next two hours.
Manipulated/Ind Variable:
-the Cereal
Responding/Dep Variable:
their behavior
This is your main experiment.
Can also be called the experimental group
Next do a control experiment
(see next slide)

26. Notes Experiment Control Experiment (Fruity Pebbles Example)
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
(Fruity Pebbles Example)
Experiment
Does eating a sugary cereal make children hyperactive?
Every day for a week have 3 children eat a bowl of Fruity Pebbles.
Then observe their energy level for the next two hours.
Manipulated/Ind Variable:
-the Cereal
Responding/Dep Variable:
-their behavior
Do a control experiment by simply removing the independent variable entirely or replace it with a neutral independent variable.
Option 01: Repeat the experiment exactly except this time don't give the children any cereal at all.
Option 02: Repeat the experiment exactly but give them a bowl of cereal that does not contain any sugar.

27. Example: 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.
The independent variable is the distance from the sunlamp
Corn plant 01
Corn plant 02
Corn plant 03
Do a control experiment by simply removing the independent variable entirely or remove its affect
control experiment-place one other corn plant in a dark room

28. Notes Experiment Control Experiment (Energy Drink Example)
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
Experiment
If you consume an energy drink before running
will it enable you to run faster?
On 3 different days at the track, consume one can of energy drink.
(Day 1: Monster, Day 2: Red Bull, Day 3: Rock Star)
Then run 30 meters as fast as you can.
Record the time it takes you to run that distance.
(Energy Drink Example)
Manipulated/Ind Variable:
-type of energy drinks
Responding/Dep Variable:
-how fast you run
This is your main experiment.
Can also be called the experimental group
Next do a control experiment
(see next slide)

29. Notes Experiment Control Experiment (Energy Drink Example)
SPI 0807.Inq.1
(Variables and Controls)
Notes
Science
Experiment
If you consume an energy drink before running
will it enable you to run faster?
On 3 different days at the track, consume one can of energy drink.
(Day 1: Monster, Day 2: Red Bull, Day 3: Rock Star)
Then run 30 meters as fast as you can.
Record the time it takes you to run that distance.
(Energy Drink Example)
Manipulated/Ind Variable:
-type of energy drinks
Responding/Dep Variable:
-how fast you run
Do a control experiment by simply removing the independent variable entirely or remove its affect
control experiment-run one more time without an energy drink or have a
glass of water instead.

30. Exit Ticket – SPI 0807.Inq.1 Controls

31. 2

32. 3

33. 4

34. Dependent Independent Text Sent/ Data Used Cell Phone Bill
The amount of gas you have
Hours of sleep per night
Cell Phone Bill
How far you can drive
Waking up on time

35. Independent Dependent Number of XBOX achievements earned
How many tardies you have
How fast you drive
Who scores more points
Temperature
Number of Whoopers
Bottles of water drank
Higher gamer score
Loss of locker for 1 week
Time it takes to drive somewhere
Result of a football game
Wearing shorts or long pants
Total calories and fat
Number of bathroom breaks

36. Variables and Controls
Day 3

38. Paper Airplanes
Question: Does changing the size of the paper affect how far a paper airplane flies?

39. 1. Start off by preparing three pieces of paper with the same ratio of height and width.   *8.5×11 inches *7×9.5 inches *5.5 x 8 inches.

40. 2. Fold the papers into the same design for all three
2. Fold the papers into the same design for all three.  The design doesn’t really matter.

41. 3. Use the same force to throw the airplanes
3. Use the same force to throw the airplanes. Measure how far each one flies.  (You may want to do multiple trials, although that is not the point of the lesson.)  Record data

43. Variables and Controls
Day 4

44. Identify Independent Variables, Dependent Variables, and Controls
EXPERIMENT 1 Group Review:
One time when Ms. Ryland went to the grocery store she bought all the types of microwave popcorn that the store had. With these types of popcorn she conducted an experiment.
Scientific Question: Does the amount of butter on the popcorn kernels affect the number of kernels that pop?
Review the hypothesis that you created in the hypothesis practice. Identify the IV, DV, and constants that would be necessary to conduct this experiment AND have the results be VALID.
Independent variable: ________________________________________________________________________
Dependent variable: _________________________________________________________________________
Constants: _________________________________________________________________________________
__________________________________________________________________________________________

45. Identify Independent Variables, Dependent Variables, and Controls
EXPERIMENT 2 Group Review:
Kelly proposes the idea that the marble would travel at a faster pace if it is rolled down the longer slide. This discussion leads to the following scientific question. What happens to the speed a marble travels when the height of a ramp is changed?
Review the hypothesis that you created in the hypothesis practice. Identify the IV, DV, and constants that would be necessary to conduct this experiment AND have the results be VALID.
Independent variable: ________________________________________________________________________
Dependent variable: _________________________________________________________________________
Constants: _________________________________________________________________________________
__________________________________________________________________________________________

46. It’s Your Turn
On your own, complete the Independent Variable, Dependent Variable, and Control activity.