Scientific Method study guide

There will be a test on the scientific method on Friday, March 7. For the test, students will need to understand the parts of an experiment. Here's a study guide for the vocabulary terms.

independent variable = the variable that is purposely changed by the scientist in order to see if the dependent variable changes with the independent variable; you can also think of this as the difference in your groups. 

dependent variable = the variable observed and/or measured during the experiment to find out if it changes with the independent variable 

controlled variables = all the things that could change but the scientist keeps the same to prevent them from interfering with the experiment 

hypothesis = a prediction of what you will find in your experiment; a predicted answer to your scientific question; a hypothesis is usually stated as an if/then statement.
Important detail: A scientific hypothesis must be testable.

In our class experiment, we had the question, "Do 7th grade DRMS boys have better hand-eye coordination for throwing than 7th grade DRMS girls?"

Our hypothesis was, "If I compare the accuracy of 7^th grade DRMS males and females at throwing tennis balls into a trash can, then it will be found that males are more accurate than females."

Our independent variable was the gender of the people--boys vs girls. That's what we changed about the groups.

Our dependent variable was the number of baskets scored by each person. That is what we measured to see if it changed with the groups.

Our controlled variables included everyone using the same tennis balls, standing the same distance away, throwing at the same trash can, in the same room, having the same number of tries, etc.

Remember that the independent and dependent variables will be in the hypothesis. The "if" part contains the independent variable, and the "then" part contains the dependent variable. In our experiment, the "if" was comparing boys and girls, and the "then" was the number of baskets scored per person. You should be able to determine the independent and dependent variables by looking at the hypothesis.

Here's another practice problem:

Billy Bob wanted to know if organic pesticide works better than artificial pesticide at preventing oleander caterpillars from attacking his oleander plant. After reading about other people's experiments, he learned that most researchers have found organic pesticides are less effective. So, he developed this hypothesis:
"If organic pesticides and artificial pesticides are compared in their ability to prevent oleander caterpillars from attacking oleander plants, then it will be found that oleander plants treated with organic pesticides will have more caterpillars than oleander plants treated with artificial pesticides."

1) What is the independent variable?
2) What is the dependent variable?
3) What are three controlled variables needed for this experiment?