THE Name : ______

SCIENTIFIC METHOD

Write a definition for each:

Independent Variable - a change that occur in an experiment that are directly caused by the experimenter

Dependent Variable - a change that occurs due to independent variables (no direct control)

Control Variables- other variables that could influence the dependent variable (must be kept constant).

Control Group - the group of test subjects left untreated or unexposed to an independent variable

Experimental Group - the group of test subjects treated or exposed to an independent variable

PRACTICE

Smithers thinks that Red Bull will increase the productivity of workers. He creates two 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 Red Bull to drink while they work. Group B is not given the Red Bull. After an hour, Smithers counts how many stacks of papers each group has made. Group A spent most of their time talking and running around in circles and only made made 1,587 stacks, Group B made 2,113 stacks.

1. What is the Control Group

2. What is the Independent Variable

3. What is the Dependent Variable

4. What should Smithers' conclusion be?

5. How could this experiment be improved?

Homer notices that his shower is covered in a strange green slime. His friend 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.

1. What is the Control Group

2. What is the Independent Variable

3. What is the Dependent Variable

4. What should Homers' conclusion be?

Bart believes that mice exposed to microwaves will become extra strong (maybe he's been reading too much Radioactive Man). 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. 7 out of 10 of the non-microwaved mice were able to do the same.

1. What is the Control Group

2. What is the Independent Variable

3. What is the Dependent Variable

4. Bart concluded that microwaving mice made them stronger. Is this a good conclusion?

5. What could Bart do to make this experiment better?

Krusty was told that a certain itching powder was the newest best thing 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. One test subject (A) is sprinkled several times with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. The total time itching was recorded as follows .

Trial #1 / Trial #2 / Trial #3 / Trial #4
Subject A / 10 min / 11 min / 9 min / 10 min
Subject B / 15 min / 17 min / 14 / 15

1. What is the Independent Variable

2. What is the Dependent Variable

3. Do the results support the products claim?

4. Are the results reliable? Why or why not?

Lisa is working on a science project. Her task is to answer the question: "Does Rogooti (which is a commercial hair product) affect hair growth". Homer is willing to volunteer for the experiment.

1. What should her Independent Variable be?

2. What should her Dependent Variable be?

3. What control Variables should she set?

4. Will her results be reliable? Why or why not?

Real World Practice

A ) Put the following in order based on the correct order of the scientific process

____ The scientist publishes an article that claims the new drug is a rip off

____ A scientist wants to know how well a new drug works that claims it can help you do better on tests

____ The scientist grades the tests of each group before and after the drug is taken. He finds little improvement in both groups

____ The scientist believes that the drug will not help you score better on tests but he has no proof

____ The scientist follows his plan and begins testing each group

____ The scientist puts together a plan to give a test to a group of 40 people. After the test he will break the group into two at random. The first group (group A) will take the new drug. The second group (group B) will take a fake pill. Afterwards both groups will take the test.

B) In the experiment above what is the independent variable?

C) In the experiment above what is the dependent variable?

D) Which group is the control group in the experiment?

Homework

For each of the questions below, write a hypothesis and create an experiment to test the hypothesis. List the independent and dependent variables of your experiment as well as all of the control variables needed to ensure good experimental results.

Question / Hypothesis / Independent Variable (What I change) / Dependent Variables (What I observe) / Controlled Variables (What I keep the same)
How much water flows through a faucet at different openings? / If the faucet opening increases then the amount of water flow will increase / Water faucet opening (closed, half open, fully open) / Amount of water flowing measured in liters per minute / .The Faucet .Water pressure( or how much the water is "pushing")
Does fertilizer make a plant grow bigger?
Does heating a cup of water allow it to dissolve more sugar?
Who listens to music the most: teenagers or their parents?
How fast does a candle burn?