The Scientific Method

1. The Scientific Method

2. He observed flies hovering around dead animals Meet Francesco Redi: 1. Observation • You have observed something and want to know more. There is a question or problem.

3. 2. Research • Find out what is already known about the subject. Redi knew that the current idea was “Spontaneous Generation” – that maggots grew directly from the dead animals. He was not convinced.

4. 3. Hypothesis • Make an educated guess Redi thought that perhaps the maggots came from eggs laid by the flies.

5. 4. Experiment • Design an experiment to test your hypothesis. Redi set up jars with dead animals in them. Half he left open. These are his control group. He knew what to expect.

6. 4. Experiment • Design an experiment to test your hypothesis. Half he covered with gauze. This was his experimental group. He changed only ONE thing – the independentvariable. The dependent variableis what you are measuring and will change based on/depending on the independent variable. Redi’s dependent variable: maggots or no maggots Redi’s independent variable: gauze or open

7. 4. Experiment • Design an experiment to test your hypothesis. Redi left the jars outside for 1 week and then looked for maggots on the dead animals.

8. 5. Compile Data • Your experiment will give you a lot of information. RECORD IT! Make charts, graphs, drawings, whatever! Redi’s data:

9. 6. Conclusion • Based on the data collected, draw a conclusion. Either your hypothesis was correct or it was incorrect. Or perhaps your experiment just didn’t work out and you need to go back to #4 – experiment. Redi concluded that his hypothesis was correct: maggots do not just grow out of dead animals. They grow from eggs laid by flies. If you stop flies from getting to dead animals, no maggots can grow on them.

10. Do it all again! • Science requires many trials – the experiment must be repeated several times before it can be considered “proven.” • If each experiment shows the same results, the hypothesis can become a theory. • Theory: “A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.”1 1http://www.thefreedictionary.com/Scientific+theories

11. Put it all together! Observe an unexplained phenomenon. Collect information. Make observations. Ask questions. Use prior knowledge. Review related research. Form a hypothesis. Design an experiment to test the chosen hypothesis. Conduct an experiment and record the data. Compare Expected results Actual results Repeat experiment many times until results are consistent. Draw a conclusion Refine and test an alternate hypothesis. Hypothesis is supported Hypothesis is not supported Report results of the experiment Compare results from similar experiments. Additional experimentation based on accepted hypothesis Accepted hypothesis Leads to http://thesciencebeat.pbworks.com/f/1279725362/Scientific%20Method.jpg

12. Put it all together! http://thesciencebeat.pbworks.com/f/1279725362/Scientific%20Method.jpg

13. Be Careful! • The Scientific Method does not always go as planned. • You may wind up on any step at any time! • There are many different models of the scientific method, but the main idea is the same.