1. Topic: Nature of Science MI: Scientific Method

2. What is the Scientific Method? Universal approach to scientific problems Universal approach to scientific problems

3. Steps of the Scientific Method 1. Define the problem (?) 2. Form a hypothesis: an educated guess (I think….) 3. Gather materials needed 4. Perform a controlled experiment to test the hypothesis 5. Make observations 6. Organize the results or data collected 7. Draw a conclusion

4. Controlled Experiment Controlled Experiment - There must be 2 or more groups: -Experimental group  contains the variable -Control group  does NOT contain the variable Everything between the 2 groups must be exactly the same except for the variable!!!!!

5. What is the variable? What is the variable? The factor in the experiment that can change The factor in the experiment that can change 2 types 2 types –Independent variable  the ONE factor that is DIFFERENT between the experimental group and the control Examples: temperature, light, light intensity Examples: temperature, light, light intensity –Dependent variable  influenced by the independent variable What you will measure / DATA or results you observed What you will measure / DATA or results you observed

6. What is the control? What is the control? Separate setup exactly like the experimental group EXCEPT it does not contain the variable Separate setup exactly like the experimental group EXCEPT it does not contain the variable

7. What must be done to make the results of an experiment reliable / accurate / valid? REPEAT the experiment (without changing the control or variable) and obtain the same results REPEAT the experiment (without changing the control or variable) and obtain the same results A larger sample size A larger sample size Only one variable Only one variable

8. What is a theory? A hypothesis supported by many experiments A hypothesis supported by many experiments Thought to be true but can be changed Thought to be true but can be changed

9. Example Sandy wants to test the effect of rap music on pea plant growth. She plays loud rap music 24 hours a day to a series of pea plants grown under light, and watered every day. At the end of her experiment she concludes rap is conducive to plant growth. Her teacher grades her project very low. Why??????? Sandy wants to test the effect of rap music on pea plant growth. She plays loud rap music 24 hours a day to a series of pea plants grown under light, and watered every day. At the end of her experiment she concludes rap is conducive to plant growth. Her teacher grades her project very low. Why???????

10. Sandy returns to her experiment, but this time she has a separate group of plants under the same conditions as the rapping plants, but with soothing Led Zeppelin songs playing. She comes to the same conclusion as before, but now has a basis for comparison. Her teacher gives her project a better grade. Sandy returns to her experiment, but this time she has a separate group of plants under the same conditions as the rapping plants, but with soothing Led Zeppelin songs playing. She comes to the same conclusion as before, but now has a basis for comparison. Her teacher gives her project a better grade. 1. Give the problem and hypothesis of this experiment. 2. What was the independent variable? 3. What was the dependent variable? 4. What should be done to make the results of Sandy’s experiment more reliable?