The Scientific Method TSW identify the steps of the scientific method & differentiate between IV & DV

Steps of the Scientific Method Problem/Question Observation/Research Formulate a hypothesis Experiment Collect and analyze results Conclusion Communicate the results

1. Problem/Question What do you want to know? Must be able to solve through experimentation

2. Observation/Research Investigate your topic of research

3. Formulate a Hypothesis Predict a possible answer to the problem or question Example: If soil temperatures rise, then plant growth will increase.

4. Experiment Develop and follow a step-by-step procedure Be specific so that other scientists can duplicate your experiment

4a. Independent Variable The manipulated variable What “I” choose to change Example: If soil temperatures rise, then plant growth will increase.

4b. Dependent Variable The responding variable What changes in response to changes made to the IV Example: If soil temperatures rise, then plant growth will increase.

4c. Control Group that receives none of the IV May be a “no treatment” group or an “experimenter selected” group Serves as a standard of comparison for other trials

4d. Constants All factors that an experimenter chooses to keep the same

5. Collect & Analyze Results Confirm results by retesting Include tables, graphs, diagrams, photos, etc.

6. Conclusion Decide whether to accept or reject your hypothesis Make recommendations for further study or improvements to your experiment

7. Communicate the Results Discuss your results with an audience

Think you can remember all 7 steps?

Let’s apply our knowledge of the Scientific Method to a realistic example. What’s the first step?

1. Problem/Question John watches his grandmother bake bread. He asks her what makes the bread rise. She explains that yeast in the dough releases a gas as it feeds on sugar. What might John’s question be?

1. Problem/Question Does the amount of sugar used in the recipe have an effect on the size of the bread loaf?

2. Observation/Research John researches the areas of baking and fermentation and tries to come up with a way to test his question. What does he need to do next?

3. Formulate a Hypothesis If more sugar is added to the dough, then the bread will rise higher. Notice that there is a direct relationship between the IV and the DV.

4. Experiment John’s teacher helps him come up with a step-by-step procedure and a list of needed materials. She discussed with him how to determine the IV, DV, control and constants.

4a. Independent Variable What did John choose to change in this experiment? IV: The amount of sugar added to the dough Example: 25g., 50g., 100g., 250g.

4b. Dependent Variable What responded to the changes in the amount of sugar? DV: The height of the rising bread What’s next?

4c. Control Since John’s grandmother always used 50g. of sugar in her recipe, John decided to use that amount in his control group. This will be his standard of comparison.

4d. Constants Can you think of any constants for John’s experiment? Example: Other ingredients in the recipe, oven used, rise time, type of pan used, oven temperature, age of the yeast, etc…

Collect & Analyze Results Size of Baked Bread (cm³) Amount of Sugar (g.) 1 2 3 Average size (cm³) 25 g. 768 744 761 758 50 g. 1296 1188 1260 100 g. 672 576 588 612 250 g. 432 504 360

6. Conclusion What do you think? Should John accept or reject his hypothesis?

7. Communicate the Results John tells his grandmother about his results and prepares to present his findings to his classmates.