How is Science Made?

1. Scientific Method How is Science Made?

2. Observation • 1.Observation: See that there is a problem. • -Most students recognized that there was a big stain on my shirt • -Make sure there is only one problem being studied!!!

3. Research the Problem • Look up everything you can on your topic • Visit your library or go on the internet • Conduct personal interviews • Search for articles (magazines, journals, books, newspapers) that have been written about the topic you are interested in

4. Hypothesis • 2.Hypothesis: an educated guess • -Possible answers to questions generated by your observations • -Typically written as an “if and then” statement • -“If’ =hypothesis • -“Then” = results received after the controlled experiment.

5. Example of “if” “then” hypothesis • "If a plant receives fertilizer, then it will grow to be bigger than a plant that does not receive fertilizer.”

6. **It involves a prediction, which explains the problem. • Ex. of a prediction:The spot on Mrs. Gates shirt is oil • Then use that prediction to make a hypothesis. • Ex: If the spot on Mrs. Gates shirt is oil, then the spot should look and smell like oil.

7. 3. Experiment: Develop and conduct a controlled experiment. -Test one variable at a time Experiment

8. Ex: compare the smell on my shirt to regular oil. Dump oil on an identical shirt and see if the spots look similar. Also put ink, paint, and dirt on the same shirt and compare those spots to the “mystery spot.”

9. An experiment must have a controlled variable and a manipulated variable • Control: Serves as a standard for comparison. The control must remain the same throughout the experiment. Ex: the shirt that I am wearing will be the control. • Variable: A variable that is being changed in the experiment. Ex: the spots of ink, paint, dirt, and oil are the variables in this experiment.

10. Qualitative vs. Quantitative Data Quantitative -Data that uses numbers -(Height- John is 6’2” Weight- 195 lbs ) Qualitative -Descriptive, no numbers -Involves characteristics that can’t be measured -Ex. Study of how gorillas behave

11. Components of a controlled experiment A. Control setup Setup in which all conditions are kept the same B. Experimental setup Setup in which all conditions are kept the same except for the one being tested C. Independent variable The condition (variable) being changed by you D. Dependent variable The condition (variable) being observed or measuredin the experiment Problem: Does the level of iron in a mouse’s diet affect the number of its red blood cells? A. Control setup Normal mouse feed (what is normally fed to the mouse everyday) B. Experimental setup Mouse fed different levels of iron in the feed C. Independent variable Different amounts of iron added/subtracted from the feed D. Dependent variable Number of red bloodcells

12. Record Results • 4. Record results: Scientists must keep accurate records of data and observations. • Ex: write down the differences and similarities of the different spots.

13. Analyze Results • 5. Analyze results: Make sense of the data. • Ex: which spots smelled and looked more similar to the “mystery spot.”

14. Conclusion • 6. Make a conclusion: Was your hypothesis supported or proven false. You cannot “prove” a hypothesis after just one experiment. It is not correct to say that the hypothesis was proven correct. • It is correct to say that the data supports my hypothesis.

15. Ex: the data supported our hypothesis that the spot on Mrs. Gatesshirt was oil.

16. Scientific Method Flowchart Observation Hypothesis Experiment Record Results Analyze Results Conclusion

17. Redi’s Experiment on Spontaneous generation • Spontaneous generation: About 400 years ago, scientists believed that life arose from non-living matter. Ex: the spot of oil on my shirt will spontaneously turn into a bird!!! • People once thought that meat magically transforms into flies. • Francesco Redi (1668) designed a controlled experiment to try and prove this idea false. • Needham and Spallanzani’s experiments • Needham was not convinced that spontaneous generation did not exist!!!

18. Redi’s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Covered jars Uncovered 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 Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

19. Spallanzani’s Experiment Flask is open. Gravy is teeming with microorganisms. Gravy is boiled. Flask is sealed. Gravy is free of microorganisms. Gravy is boiled.

20. Observation vs. Inference • Observation: -Interpretation using one or more of the senses. Ex: That object is big, green, soft, and heavy • Inference: -Is an interpretation based on ones prior knowledge and/or experience. Ex: The sun makes that tree grow tall .

21. Observation or Inference? Statement Observation Inference Object A is round and orange. X X Object A is a basketball. Object C is round and black and white. X Object C is larger than Object B. X Object B is smooth. X X Object B is a table-tennis ball. Each object is used in a different sport. X