The Scientific Method A universal approach to scientific problem solving through a series of well-defined steps

PROBLEM 1- Defining the Problem -Stated in the form of a question that defines a specific problem for investigation Ex- Do plants need water to grow? Does sugar make kids hyperactive? Does a full moon cause an increase in abnormal behavior?

RESEARCH 2- Research the Problem - Library, internet, periodicals, textbooks, encyclopedias, newspaper, scientists, teachers, TV

HYPOTHESIS 3- Develop a Hypothesis (educated guess) - A possible explanation for an observed set of facts - Reasoning, guesswork, and inspiration Ex- Plants need water to grow Sugar makes kids hyperactive Abnormal behavior does not increase during a full moon

PROCEDURE 4- Procedure (Design an experiment to test the hypothesis) - list of materials - detailed and easy to follow step by step set of instructions for carrying out experiment

PROCEDURE Variable- A factor that changes in an experiment Independent variable- factor which is changed as part of the procedure (what is being tested) Ex- watering plants Dependent variable- factor that changes as a result of the procedure (changes because IV changes) Ex- plant growth

PROCEDURE Constant- Factors that are not changed (Ex- plants, soil, sunlight, location) Control- No factors are changed, a reference setup, standard for comparison Sample Size- adequate, observable subjects (not too few, not too many)

TEST 5- Test the Hypothesis - experiment and results must be repeatable to be valid Ex- Plants that are not watered do not grow

DATA 6- Record and Organize Data Observations – What happened during experiment Qualitative Observations- descriptions based on observer’s senses (Ex- Watered plants are taller) Quantitative Observations- accurate measurements and numerical results obtained using tools and instruments (Ex- The watered plants grew 3 inches more than those that were not watered)

DATA Record Data- Charts, graphs, Tables, Diagrams, Photographs Analyze Data- Look for patterns or relationships Inference- Deductions based on prior experience

CONCLUSIONS 7- Interpret results and draw conclusions Does data support, modify or disprove hypothesis? The conclusion is the answer to the original problem and should prove or disprove the hypothesis Ex- Plants need water to grow

Observation vs Inference Observation: The grass on the school lawn is wet What are some inferences that we could make?

Possible Inferences It rained The sprinkler was on There was dew on the grass Someone had a water balloon fight A dog urinated on the lawn

Observation vs Inference

Observation/Inference Observation: Lisa got a 100% on a biology test! Inference: ? She is very smart! She will hang it on the refrigerator! She is good in science! She will get a good progress report! She studied a lot!

How good of an observer are you?

REPORT All aspects of an experiment must be recorded accurately and reported in detail so that it can be repeated by other investigators Published in scientific journals

THEORIES Explanations that apply to a broad range of phenomena and are supported by experimental evidence, attempts to explain the cause of the phenomena Ex- The Theory of Evolution

SCIENTIFIC LAW Describe an aspect of a phenomena that is always true, a particular event or relationship always exists under certain conditions Does not explain how or why Ex- Law of Gravity

Frans de Waal: Moral behavior in animals

Richard Turere: My invention that made peace with lions

Will mice who receive Coke run faster on the wheel? PRACTICE Question: Will mice who receive Coke run faster on the wheel?

Experimental Group of Mice Control Group of Mice Experimental Group of Mice 100 mice 100 mice Constants: Same type of mice Same size of cage Same gender Same food Same temperature Same time of day

Coke IF ______________THEN _____________ Independent Variable Control Group of Mice Experimental Group of Mice 100 mice 100 mice Independent Variable Dependent Variable Coke IF ______________THEN _____________ Faster running

that seeds would start to grow faster Stephen thought that seeds would start to grow faster if an electric current traveled through the soil in which they were planted. Question Hypothesis Experiment Results Conclusion

Rene grew bacteria from the mouth on special plates in the laboratory. She placed drops of different mouthwashes on bacteria on each plate. Question Hypothesis Experiment Results Conclusion

Jonathan’s data showed that household cockroaches moved away from raw cucumber slices. Question Hypothesis Experiment Results Conclusion

Kevin said, “If I grow five seedlings in red light, I think the plants will grow faster than the five plants grown in white light.” Question Hypothesis Experiment Results Conclusion

Kevin said, “If I grow five seedlings in red light, I think the plants will grow faster than the five plants grown in white light.” Question Hypothesis Experiment Results Conclusion

Practice experiments Do plants grow better with fertilizer?

Control Group= Does not get the variable. Experimental Group= Receives the variable Constants= The factors that must remain constant between the two groups.

Ms. Romer YOU CAN ONLY CHANGE ONE FACTOR. Fertilizer Ms. Romer

Which factors should remain constant? Sunlight Water Type of plant Age of plant Size of plant Throw out your work and start over! What if you don’t keep these the same?

Hypothesis: I think fertilizer will help bean plants grow taller. Ms. Romer Hypothesis: I think fertilizer will help bean plants grow taller. Procedure: You take a bean plant and give it 4 scoops of fertilizer per day. You watch it grow for 3 weeks. No Control Group Ms. Romer

Hypothesis: I think fertilizer will help bean plants grow taller. Ms. Romer Hypothesis: I think fertilizer will help bean plants grow taller. Procedure: You take a bean plant and give it 4 scoops of fertilizer per day. You watch it grow for 3 weeks. No Control Group Ms. Romer

Procedure: You use 2 plants. Ms. Romer Procedure: You use 2 plants. One has no fertilizer, one has 4 scoops per day. Ms. Romer

What can we fix about this experiment? Ms. Romer What can we fix about this experiment? Use more plants!! Ms. Romer