1. An organized set of investigation procedures
Scientific Method
An organized set of investigation procedures

2. Steps of the Scientific Method
1. State the problem
The “how” or “why”
2. Gather information
3. Form a hypothesis
A possible explanation for a problem using what you know and what you observe
A suggested explanation for an observation

3. Steps of the Scientific Method
4. Test the hypothesis by performing an experiment
5. Analyze data
Record observations
Organize data into tables and graphs

4. Steps of the Scientific Method
6. Draw conclusions
If your data supports the hypothesis, your hypothesis was correct.
If your data does not support the hypothesis, your hypothesis was not correct. Change your hypothesis and begin again.

5. Steps of the Scientific Method

6. Experiments Tests the effect of one by using controlled conditions
Uses variables or a quantity that can have more than a single value

7. Variables
Independent: the variable you can change or manipulate to see how it affects the dependent variable
Dependent: the variable that changes because of the independent variable

8. Variables
Constant: a factor that does not change when other variables change
Control: standard by which the test results can be compared

9. Special Juice
Smithers thinks that a special juice will increase productivity of workers. He creates 2 groups of 50 workers each and assigns each group the same task (in this case, they’re supposed to staple a set of papers). Group A is given the special juice while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of paper each group has made. Group A made 1,587 stacks and Group B made 2,113 stacks.
Identufy the:
Control Group
Group B
Independent Variable
Special Juice
Dependent Variable
Productivity of workers
What should Smithers’ conclusion be?
The special juice did not increase workers productivity
How could this experiment be improved?
Retest it!

10. Who needs a clean shower?
Homer notices that his shower is covered in a strange green slime. Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of “treatment” there is no change in the appearance of the green slime on either side of the shower.
What was the initial observation?
Green slime on the shower
Identify the:
Control Group
Side sprayed with water
Independent Variable
Coconut juice
Dependent Variable
The appearance of green slime
What should Homer’s conclusion be?
Coconut juice did not reduce the amount of slime in the shower

11. Microwave is not only for food!
Bart believes that mice exposed to microwaves will become extra strong. He decides to perform this experiment by placing 10 mice in a microwave for 10 seconds. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. He found that 8 out of 10 of the microwaved mice were able to push the block away while 7 of the 10 non-microwaved mice could do the same.
Identify the:
Control Group
Mice that had not been exposed
Independent Variable
Microwave
Dependent Variable
Strength of the mice
What should Bart’s conclusion be?
Microwaving caused the mouse to stronger than non- microwaved mice
How could Bart’s experiment be improved?
Retest it

12. The “Itch” Factor
Krusty was told that a certain itching powder was the best on the market. It even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. Test subject A is sprinkled with the original itching powder and Test subject B was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes while Subject B reported to have itches for 45 minutes.
Identify the:
Control Group
Group A
Independent Variable
Experimental Itching Powder
Dependent Variable
Itchiness Timing
Explain whether the data supports the advertisements claims about its product.
The itchiness time was increased by ½ of the claim is supported.

13. Hair-Do
Lisa is working on a science project. Her task is to answer the question: “Does Rogooti (which is a commerical hair product) affect the speed of hair growth?” Her family is willing to volunteer for the experiment.
Describe how Lisa would perform this experiment. Identify the control group, the independent variables, and the dependent variables in your description.
Have 2 people (control group) use a “fake” hair care product and 2 people use Rogooti (independent variable). Measure hair growth (dependent variable) over 4 weeks for each subject.