1. Controls, Variables, Simpsons and SpongeBob, OH MY!
Scientific Method
Controls, Variables, Simpsons and SpongeBob, OH MY!

2. Testable Questions
In order to solve many scientific questions, scientists form what are called
TESTABLE QUESTIONS
What would be an example of a testable question?
Most testable questions have:
An Manipulated (independent) variable
&
A Responding (dependent) variable

3. Testable Questions
Does changing the height of the ramp affect the speed of the car going down the ramp?
A testable question can be answered through research or experimentation. It is not an opinion.

4. The SINGLE item that will be changed in an experiment
Variables
Manipulated/Independent Variable
The SINGLE item that will be changed in an experiment
Height of the Ramp
Ramp 1 Ramp 2 Ramp 3

5. Speed of the Car Variables Responding/Dependent Variable
It is what changes BECAUSE of the manipulated/ independent variable
The item that will be measured in an experiment
Speed of the Car

6. Manipulated Variable Responding Variable
Testable Question #1
Manipulated Variable
Does changing the height of the ramp affect the speed of the car going down the ramp?
Responding Variable

7. Other parts of a TESTABLE question
Controlled Variables (a.k.a Constants)
The conditions that are kept the same (unchanged) in an experiment
Same car
Same ramp surface
Same surface the car travels on
All of these things help to make the test FAIR and Reliable!

8. Control Group
Does watering a plant with coffee make the plant grow faster?
What are we testing? (the independent variable?)
If coffee increases growth
How are we going to know if coffee makes a plant grow faster?
NEED TO HAVE A COMPARISON- the CONTROL GROUP
What would the control group be??
Watering with PLAIN WATER

9. Controls and Variables Practice
Ready for some clicker questions???

10. Does the type of bubble gum chewed affect the size of the bubble
Does the type of bubble gum chewed affect the size of the bubble? Identify the INDEPENDENT VARIABLE
Type of bubble gum
Size of the bubble
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11. What will the dependent variable measure for the gum question?
Does the type of bubble gum chewed affect the size of the bubble?
What will the dependent variable measure for the gum question?
Type of gum
Time gum is chewed
Size of bubble
Number of bubbles
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12. Does watering a bean plant with gatorade affect the growth of the plant? Identify the DEPENDENT VARIABLE
Watering a bean plant
Growth of the plant
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13. The plant watered with gatorade The plants watered with water
Does watering a bean plant with gatorade affect the growth of the plant?
For the bean plant question, what would be the CONTROL for this experiement?
The gatorade
The plant watered with gatorade
The plants watered with water
The water
Response Grid
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14. Krusty Krabs Breath Mints
Mr. Krabs created a secret ingredient for a breath mint that he things will “cure” the bad breath people get from eating crabby patties at the Krusty Krab. He asked 100 customers with a history of bad breath to try his new breath mint. He had 50 customers (Group A) eat a breath mint after they finished eating a crabby patty. The other 50 (Group B) also received a breath mint after they finished the sandwich, however, it was just a regualr breath mint and did not have the secret ingredient. Both groups were told that they were getting the breath mint that would cure their bad breath. Two hours after eating the crabby aptties, thirty customers in Group A and ten customers in Group B reported having better breath than they normally had after eating crabby patties.

15. Which people are the control group?
Mr. Krabs
Group A
Group B
Why is this the control group???
Group B didn’t get the breath mint with the special ingredient.
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16. What is the independent variable?
Bad breath
Special breath mint
Regular breath mint
Clean breath
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17. What is the dependent variable?
Bad breath
Special breath mint
Regular Breath mint
Fresh breath
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18. What should Mr. Krab’s conclusion be?
The special breath mint helped cure bad breath
The special breath mint didn’t cure bad breath
There is no way to know if the special breath mint worked
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19. Why do you think 10 people in group B reported fresher breath?
They were confused
They thought they had the special mint
They were given a mint
They never had bad breath
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20. SpongeBob Clean Pants
SpongeBob noticed that his favorite pants were nto as clan as they used to be. His friend Sandy told him that he should try using Clean-O detergent, a new laundry soap she found at Sail Mart. SpongeBob made sure to was one pair of pants in plan water and another pair in water with the Clean-O detergent. After washing both pairs of pants a total of three times, the pants washed in the Clean-O detergent did not appear to be any cleaner than the pants washed in plain water.

21. What is the problem that SpongeBob wanted to investigate?
Why are his pants dirty?
Will plain water clean his pants?
Does Clean-O detergent work?
How many washes does it take to clean his pants?
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