Scientific Method with SpongeBob
Controls and Variables
Name: __________________________
Date: __________________ pd: _____
I. Write a definition for each of the following words in YOUR own words. Yes look them up but
don’t copy!
 Control – Variables that are kept the same throughout experiment; part of experiment used
to compare to
 Variable – Factors that can or do change during an experiment

Independent variable – Factor changed by the experimenter to test the hypothesis (I change)

Dependent variable – Factor that changes because of the independent variable; measureable
(data)
II. SpongeBob and his Bikini Bottom pals have been busy doing a little research. Read the
following description for each of their experiments and answer the questions provided.
Krusty Krabs Breath Mints
Mr. Krabs created a secret ingredient for a breath mint that he thinks 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 customers (Group B) also received a breath mint after they
finished the sandwich, however, it was just a regular 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 patties, 30
customers in Group A and 10 customers in Group B reported having better breath
than they normally had after eating crabby patties.
1. Which group of people were in the control group? Group without the secret ingredient, group B
2. What is the independent variable? The secret ingredient
3. What is the dependent variable? Fresh breath
4. What do you think Mr. Krabs’ conclusion should be? The secret ingredient helps
people to have fresh breath
5. Give examples/details that support why you think in#4 what Mr. Krabs’ conclusion should be.
30 out 50 people from group A had fresh breath but only 10 out 50 people from group B did
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6. Why do you think 10 people in group B reported fresher breath?
People in group B thought they had the special mint; they don’t have bad breath as easily; they
didn’t eat as much
SpongeBob Clean Pants
SpongeBob noticed that his favorite pants were not as clean 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 SailMart. SpongeBob made sure to wash one pair of pants in plain
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 that the pants washed in plain
water.
7. What was the problem SpongeBob wanted to investigate? His pants are not as clean as they use
to be
8. What is the independent variable? Clean-O Detergent
9. What is the dependent variable? Cleanness of his pants
10. What do you think SpongeBob’s conclusion should be? Whether using plain water or Clean-O
detergent, his pants are not getting any cleaner
11. Give examples/details that support why you think in #10 what SpongeBob’s conclusion
should be? After 3 washings with Clean-O detergent and/or plain water, the pants did not get any
cleaner
Squidward’s Symphony
Squidward loves playing his clarinet and believes it attracts more jellyfish than
any other instrument he has played. In order to test his hypothesis, Squidward
played a song on his clarinet for a total of 5 minutes and counted the number of
jelly fish he saw in his front yard. He played his song for a total of 3 times on
the clarinet then repeated the experiment using a flute and then a guitar. He
also recorded the number of jellyfish he observed before he began playing an
instrument. The results are shown in the data table below.
Number of Jellyfish/Instrument
12. What is the independent variable?
Trials
No
Clarinet
Flute
Guitar
The clarinet
Music
13. What is the dependent variable?
1
5
15
5
12
The number of jellyfish
2
3
10
8
18
14. What do you think Squidward’s conclusion should be? 3
2
12
9
7
Music from both Clarinet and Guitar attract jellyfish
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15. Give examples/detail as to why you think in #14 what Squidward’s conclusion should be?
There was an average of 12 jellyfish that can when either the clarinet or guitar were played; where
as with no music there was 3 jellyfish and the was 7 jellyfish with the flute.
16. Are the results reliable? Why or why not? No, limited number of instruments tried, limited
number of trials, location could have influenced the jellyfish
17. Any suggestions of what Squidward could have done differently to gain better results?
Changed locations and tested to see if results are the same; increase number of instruments;
increase number of trials
Super Bubbles
Patrick and SpongeBob love to blow bubbles! Patrick found some
Super Bubble Soap at Sail-Mart. The ads claim that Super Bubble
Soap will produce bubbles that are twice as big as bubbles made with
regular bubble soap. Patrick and SpongeBob made up two samples of
bubble solution. One sample was made with 5oz of Super Bubble
Soap and 5oz of water, and the other was made with 5oz of regular bubble soap and
5oz of water. Patrick and SpongeBob used their favorite bubble wands to blow 10
different bubbles and did their best to measure the diameter of the bubbles as they
popped on the table. The results are shown in the data table below.
18. What did the Super Bubble ads claim?
Super Bubble bubbles will be twice as big as
regular bubble solutions’ bubbles
19. What is the independent variable?
Super Bubble
20. What is the dependent variable?
Diameter of bubbles
21. Look at the results in the data table.




Calculate the average diameter for each bubble
solution.
Super Bubble = __15.1__ cm
Bubbles
(diameter in centimeters)
Bubble
1
2
3
4
5
6
7
8
9
10
Super
Bubble
15
10
12
18
22
13
16
18
15
12
Regular
Soap
10
5
16
14
11
12
11
15
15
6
Regular Soap = __11.5__ cm
What do you think SpongeBob’s and Patrick’s conclusion should be? Results show bubbles
from Super Bubble are larger but not twice as large
22. Are the results reliable? Why or why not?
No, bubble sizes are not consistent, the diameter is changing; Super Bubble the median = 15, so
this indicates an accurate and more consistent bubble size; Regular soap median = 11/12, again a
more accurate and consistent bubble size, but the mode shows Super bubble = 12, 15, 18 so 15ish
and Regular soap = 15, therefore the bubbles are the same. Also who was blowing bubbles? How
much air? How long? This information not given.
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