The scientific method is a series of steps used to solve problems through experimentation. It includes making observations, stating the problem, forming a hypothesis, experimentation, analyzing results, and reporting conclusions. Key steps are forming a testable hypothesis, designing controlled experiments to test the hypothesis, analyzing results to accept or reject the hypothesis, and communicating findings. Examples provided demonstrate early experiments disproving spontaneous generation through controlled experiments isolating variables.

1. Scientific Method The scientific method is a series of steps taken during an experiment in order to solve a problem.

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

11. 06/08/09 Gravy is boiled . Flask is open. Gravy is teeming with microorganisms. Gravy is boiled . Flask is sealed. Gravy is free of microorganisms . Section 1-2 Figure 1-10 Spallanzani’s Experiment Spallanzani’s Experiment Theory not supported “vital force in air was killed”

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

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

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

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

16. Assessment Active Art Redi and Pasteur Assesment