1) Problem Statement: Select a topic that can only be answered by experimenting. The problem statement is always is written as a question. Hint: It is good for the question to start with “which amount” or “how will?”

When creating your problem statement for your experiment, you need be able to measure your results in some way. You also need to make sure that your question is clear and specific enough to do an experiment.

Formula for a good Problem Statement: How will the independent variable affect the dependent variable?

Example Problem Statements: How will the height of a ramp affect the distance that a car will travel? Which amount of salt dissolved in water will freeze in the shortest period of time?

In a problem statement, you want to ask how your independent variable will affect your dependent variable. What is a variable?

Variables: the factors that affect your investigation Independent Variable: What the experimenter changes on purpose in his or her experiment (ex. You change the height of the car ramp) Dependent Variable: the response that is measured (it DEPENDS on the independent variable in order to change) (ex. The distance that the car travels)

If our problem statement is “How will the amount of salt affect how quickly water freezes?” What is the independent variable? What is the dependent variable?

“How will the amount of salt affect how quickly water freezes? Independent Variable: amount of salt Dependent Variable: the time water takes to freeze

What are Constants in an experiment?

Constants = the parts of the experiment that stay the same

In order to ensure that you are actually testing the effects of the amount of salt added, you need to make sure that other variables are not changing the results What are other variables in this experiment that could change the results if we do not keep them constant?

Other variables in the experiment: Water temperature Amount of water Freezer temperature We need to keep all of these variables constant

Dependent variable: the period of time that it takes to freeze Example: Hypothesis: I think that the ice cube with the least amount of salt will freeze in the shortest period of time. Independent variable: the amount of salt that I add (that is the only thing I am changing) Dependent variable: the period of time that it takes to freeze Constants: the amount of water that I add, the temperature of the freezer

Constants: the parts of the experiment that you keep the same Try to keep all parts of your experiment the same beside the independent variable (what you are intentionally trying to change)

For example, what would happen if you did the freezing experiment with different sized glasses?

Answer: You would not just be testing to see how the amount of salt affects the time it takes water to freeze, because other variables are involved. The glass with the larger amount of water will probably take more time to freeze

Constants: Keeps everything about the experiment the same, so that only the independent variable is influencing the dependent variable