The Scientific Method

Steps to the Scientific Method(PRHEAD)

• State the Problem

• Research the Problem

• State the Hypothesis

• Experiment (Test Hypothesis)

• Observe and Record Data

• Conclusion

Step 1 - State the Problem

• In your own words, describe what you want to find out. –Ex: Which car oil will allow my

car to get the best gas mileage.

Step 2 – Research the Problem

• In order to make an educated guess (hypothesis), you need to find out more information about the problem you are trying to solve.– Ex: research various oils and their

properties.

Step 3 – State the Hypothesis• Make an educated guess about the

solution to your problem based on your research.

• This is done with an “if / then” statement. .– If I use Havoline car oil then my Lamborghini

Diablo will get better gas mileage.

Step 4 – Experiment

• This is done to test the hypothesis.

• Design an experiment that will provide data to prove or disprove your hypothesis.– Ex:Test four different car oils found

during research

Parts of an Experiment• Controlled Variable– The part of an experiment

that does not change. Held constant. (same car, driven at same time for a month, same amount of oil)

• Independent Variable – The part of an experiment that you change. (car oil)

• Dependant Variable- What you are recording/observing. It changes according to how the independent variable changes.(gas milieage)

– ONLY test one variable at a time.

Step 5 – Observation

• Observations are recorded facts about what you see during the experiment.–Graph: IV’s go on the x-axis

DV’s go on y-axis

Types of Observations

• Quantitative – Results are numerical and have a unit. (ex: 5 meters, 45 seconds)

• Qualitative – Results are descriptive . (ex: the litmus paper turned red)

Observation or Inference

Observation- See with own eyes (ex; the apple is red, it is raining outside, the window is 6ft long

Inference: What you think might be true but not sure. (ex: She is wiping her eyes, she is crying, He has hair on his shirt, he owns a cat)

Step 6 - CONCLUSION

• This is a brief statement about the results of the experiment.

• In the conclusion state if the hypothesis was correct (proved) or incorrect (disproved).

• Claim, evidence, reasoning