Scientific Method

1. Scientific Method MIAMI BEACH SENIOR HIGH MRS DIAZ

2. Why is the Scientific Method Important? Continuity Communication within the scientific community 1

3. Steps of the Scientific Method • Observation • State the problem • Form a hypothesis • Experiment • Results/Data • Analysis 2

4. Observations • Qualitative observation • Focus on the qualities of an object. • Ex. Color of an object • Quantitative observation • Characteristics of an object that can be measured. • Ex. Mass, Length 3

5. State the Problem • This problem or question is formed from your observations. • This is the question you as the scientist want answered. • Also called the “purpose”. 4

6. Form a Hypothesis • The hypothesis is a testable explanation to your problem. • “Educated Guess” is not enough. You must be able to test your explanation. 5

7. Experiment • Design an experiment that tests your hypothesis. • Control Group: test variables are kept constant “Normal Conditions” • Experimental Group: variables are changed 6

8. Variables • Variables – anything that changes throughout the experiment. • There are two types of variables: • Independent variable – the change that the experimenter controls. • Dependent variable – the change that is measured.

9. Results/Analysis • Results • This section includes all of the data and information collected. • How do you present your data? • Analysis • The data is explained and the process is wrapped up. 7

10. Spontaneous Generation – Life arises from non- living things Redi’s experiment OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggotsappear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

11. Spallanzani’s Experiment Figure 1-10 Spallanzani’s Experiment Section 1-2 Gravy is teeming with microorganisms. Flask is open. Gravy is boiled. Theory not supported “vital force in air was killed” Gravy is boiled. Flask is sealed. Gravy is free of microorganisms.

12. Figure 1-11 Pasteur’s Experiment Pasteur’s Experiment Pasteur intro Pasteur changed 1 variable in the experiment – he used a curved neck flask Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

13. Figure 1-11 Pasteur’s Experiment Section 1-2 The curved neck of the flask allowed air to mix in the jar but not bacteria Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

14. Figure 1-11 Pasteur’s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

15. Figure 1-11 Pasteur’s Experiment Section 1-2 Once the neck was removed bacteria entered and spoiled the broth Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

16. Assessment • Active Art Redi and Pasteur Assesment