The scientific method

1. The scientific method

2. The Steps • State the problem or question • Form a hypothesis • Plan and conduct an experiment • Record observations and data • Analyze data • Draw conclusions

3. Experiment Terminology • Variables—anything that can change in an experiment • Independent variable • Dependent variable • Two groups • Experimentalgroup—receives treatment • Controlgroup—does not receive treatment

4. An experiment Jose’s science fair project deals with popcorn and how well it pops. He predicts that dry corn will pop better than moist popcorn.

5. Jose’s Experiment a. State the problem. b. Write a hypothesis for Jose to test. c. What is his independent variable? d. What is his dependent variable? e. Name a variable that he should control in his experiment (a controlled variable).

6. Tree Fertilizer An experiment testing tree fertilizer selected two groves of trees. Grove one was given the fertilizer mixed with water once a week for 5 years. Grove two was given only water every week. The height of the trees were measured every month for five years. What is the Control group Experimental group Controlled variable Independent variable Dependent variable Grove two Grove one Water Fertilizer Tree growth

7. Pheromones A test was conducted to see which smell females prefer. 3 white t-shirts, one covered in deodorant, one used during a gym class, and one plain were smelled by 100 females. The females were then asked to chose the shirt they thought smelled the best. 52 picked the deodorant covered shirt, 35 picked the plain shirt, and 13 picked the gym shirt. What is the Control group Experimental group Controlled variable Independent variable Dependent variable Plain shirt Gym shirt & Deodorant shirt T-shirt Smell of shirt Preference of females

8. Arrange the following information in order based on the Scientific Method. • Take measurements of the distance objects fall, and the time it takes them to fall that distance • b) Draw a conclusion about falling objects. • c) Larger objects take less time to fall than smaller objects. • d) Does the size of an object affect the time it takes to fall? • e) Drop a number of objects.

9. d) Does the size of an object affect the time it takes to fall? **Problem or Question** • c) Larger objects take less time to fall than smaller objects. **Hypothesis** • e) Drop a number of objects. **Experiment** • a) Take measurements of the distance objects fall, and the time it takes them to fall that distance. **Record data** 5. b) Draw a conclusion about falling objects. Note: In this experiment, the hypothesis is incorrect. What should the student do next?