Welcome to Living Environment Mr. Wolff Mrs. Weissenberg

Scientific Method universal approach to problem solving.

1. Define Problem must be clearly stated and formed from making observations.

2. State the Hypothesis an educated guess about how to solve the problem. It is NEVER written as a question “if……then” statement; I think that…”

2. “I think that if plants are exposed to sunlight, then they will grow faster.”

3. Design Experiment & Collect Data a series of trials or tests are done to support or refute (disprove) a hypothesis. Data are facts collected from observations.

4. Conclusion Written report that includes: problem, hypothesis, data and outcome. The conclusion is the answer to the problem. Did the data support /refute the hypothesis?

5. Repeat Large sample sizes and multiple trials are more likely to produce valid results. For example, flipping a coin

Conclude and communicate shared results; publish, etc.

A valid experiment must: include many test subjects be consistent be repeated many times with the same results

Designing controlled experiments A controlled experiment is one where all factors are the same between two test subjects except for the single experimental variable. For example, if we wanted to test the theory of how sunlight affects plant growth, the only variable that would be changed between the two plant groups is the amount of time the plants are exposed to sunlight.

A controlled experiment is one that has two groups:

1. Control Group is used to compare your results to 1. Control Group is used to compare your results to. The experiment is NOT done to this group. Often times this group is given a placebo.

Experimental Group tests the hypothesis. This group has the independent variable in it. The experiment is done to this group. Ex: trial medication

Experiments always contain different variables: independent- the variable a scientist purposely changes, stands alone, it is not affected by other variables Ex.- time

dependent - variable the scientist wants to observe which may change because of the independent variable.

For example, a test score could be a dependent variable because there are many factors that could affect the test score. Time spent studying, amount of sleep you got the night before and eating a good breakfast could influence your test grade.

The independent variable is the X-axis. The dependent variable is the Y-axis.

A theory…. is a hypothesis that has been repeatedly tested, such as the Theory of Evolution.

When collecting data it must be taken using measurements When collecting data it must be taken using measurements. Measurements always have units attached to them. 499.9 mL