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

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

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

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.

Steps of the Scientific Method

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

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

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

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!

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

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

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.

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.