Scientific Method

Steps of Scientific Method

1. Ask a Question / Identify a Problem2. Research 3. Make a Hypothesis4. Design an Experiment5. Organize & Analyze Data6. Make a Conclusion7. Repeat experiment OR Change hypothesis

Experiments

• Control – Does not change or not tested

• Independent Variable (manipulated)– The thing that is being tested & changed by the

researcher• Dependent Variable (responding)– The results or outcome of the experiment

Validity

• Sample size– Number of items being tested

• Trial– How many times the test is run

• Large sample size Less trials• Small sample size More trials• Minimum of 3 trials needed to find an average

Data

• Qualitative (quality…is observed)– Cleaner clothes, fresher breath, etc

• Quantitative (quantity…is measured)– Height (12”), time (35 seconds)

• Data can be recorded in a table

Charts & Graphs

Patty Power

Problem: People have a lot of gas after eating Krabby patties & Mr. Krabs thinks its the special sauce that is causing the gas production so he makes a new sauce and wants to see if it really works.

Hypothesis: “If I substitute the old sauce with the new sauce, then people will not have gas.”

Experiment (100 customers with gas) 50 (Group A) eat crabby patties with the new sauce. 50 (Group B) eat crabby patties with the old sauce. Both groups were told that they were getting the new

sauce.

• Independent Variable (what is being tested?)– New sauce

• Dependent Variable (what are the results?)– Less gas

• Control Group (the group that was not being tested)– Group B (Old Sauce)

• Results (2 hours after eating crabby patties)– 30 customers in group A reported having fewer

gas problems – 8 customers in group B reported having fewer gas

problems.

Gas No Gas0

10

20

30

40

50

Group AGroup B

• Conclusion (Did he prove his hypothesis?)– Yes…more people reported less gas when they ate

the New Sauce– What about the 8 in group B that had the old

sauce?• Placebo effect – Occurs when people believe they are

experiencing the effect of something even if they did not receive the treatment• In this case, it is possible that the 8 people thought they

had less gas

Slimotosis

• SpongeBob notices that his pal Gary is suffering from slimotosis, which occurs when the shell develops a nasty slime and gives off a horrible odor.

• His friend Patrick tells him that rubbing seaweed on the shell is the perfect cure, while Sandy says that drinking Dr. Kelp will be a better cure.

• SpongeBob decides to test this cure by rubbing Gary with seaweed for 1 week and having him drink Dr. Kelp Cola for a week.

• After a week of treatment, the slime is gone and Gary’s shell smells better.

• Initial Observation?– Gary was covered in smelly slime

• Independent Variable – Seaweed AND Dr Kelp Cola

• Problem with the design?– 2 variables…he must test them one at a time

• Dependent Variable– No more smelly slime (it worked!)

Marshmallow Muscles

Larry was told that a certain muscle cream was the newest best thing on the market and claims to double a person’s muscle power when used as part of a muscle-building workout.

He buys the special muscle cream and recruits Patrick and SpongeBob to help him with an experiment.

Larry develops a special marshmallow weight-lifting program for Patrick and SpongeBob.

He meets with them once every day for a period of 2 weeks and keeps track of their results.

Before each session Patrick’s arms and back are lathered in back are lathered with the muscle cream & SpongeBob is lathered with regular lotion.

Marshmallow Muscles Results(# of times dumbbell was lifted)

Time SpongeBob Patrick

Initial 5 18

After 1 Week 9 24

After 2 Weeks 17 32

• Hypothesis?– If muscle cream is applied before each workout, person will become

twice as strong.• Independent Variable?

– Muscle cream• Control?

– SpongeBob (no cream)• Dependent Variable?

– Double the strength• Conclusion?

– Didn’t double Patrick’s strength. SpongeBob actually tripled his (Maybe exercise alone will increase strength)