Scientific Method notes
- 1. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Scientific Method
- 2. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2 Scientific Method The scientific method has these steps: 1. PROBLEM – Usually a question based on observations 2. RESEARCH THE PROBLEM 3. HYPOTHESIS – answer to the question 4. WRITE THE PROCEDURE – include materials and specific procedure 5. PERFORM THE EXPERIMENT – experimental/variable group and control group 6. COLLECT DATA and OBSERVATIONS - your observations; pictures, tables, graphs, etc.; Quantitative or Qualitative observations 7. ANALYZE DATA 8. CONCLUSION – “I/We therefore conclude that __________ because the data showed _____________ and that my/our hypothesis is correct/wrong.”
- 3. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 3 Problem
- 4. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 4 What’s the difference? A HYPOTHESIS is a testable prediction about a problem. A THEORY is an explanation backed by results from repeated tests or experiments. A LAW is a well-tested description of how something in nature works.
- 5. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 5 ObservationsObservations GatheredGathered through yourthrough your sensessenses A scientistA scientist noticesnotices something insomething in theirtheir naturalnatural worldworld
- 6. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6 Observations & QuestionsObservations & Questions AnAn exampleexample of anof an observationobservation might bemight be noticing that manynoticing that many salamanders near a pondsalamanders near a pond have curved, nothave curved, not straight, tailsstraight, tails This might lead aThis might lead a scientist toscientist to questionquestion whywhy??
- 7. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 7 Research & Gather Information Find out what isFind out what is already knownalready known Why is thisWhy is this important?important?
- 8. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 8 HypothesisHypothesis A suggested solution toA suggested solution to the problem.the problem. Must beMust be testabletestable SometimesSometimes written aswritten as If…If… Then…Then… statementsstatements PredictsPredicts an outcomean outcome
- 9. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9 HypothesisHypothesis AnAn example of aexample of a hypothesishypothesis might bemight be that the salamandersthat the salamanders have curved tails due tohave curved tails due to a pollutant in the moista pollutant in the moist soil where they live.soil where they live.
- 10. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 10 ExperimentExperiment A procedureA procedure toto testtest thethe hypothesis.hypothesis.
- 11. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11 Designing an ExperimentDesigning an Experiment Experimental design : Experimental group - goes through all the steps of the experiment and is exposed to the factor being tested. Control group - goes through all the steps of the experiment but is not exposed to the factor being tested.
- 12. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12 Controlled Laboratory Experiment ExampleControlled Laboratory Experiment Example
- 13. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13 VariablesVariables Independent variableIndependent variable the factor that the experimenter “I” changes Dependent variableDependent variable what thewhat the experimenterexperimenter observes or measures as a result of what was changed
- 14. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 14 The Control VariableThe Control Variable The experimenter makes aThe experimenter makes a special effort to keepspecial effort to keep otherother factors constantfactors constant so thatso that they will not effect thethey will not effect the outcome.outcome. Those factors are calledThose factors are called control variables.control variables.
- 15. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 15 What is the Purpose of aWhat is the Purpose of a Control?Control? Controls are NOT being tested Controls are used for COMPARISON
- 16. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 16 Example of Controls &Example of Controls & VariablesVariables For example, suppose you want to figure out the fastest route to walk home from school. You will try several different routes and time how long it takes you to get home by each one. Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.
- 17. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 17 What are the Variables in YourWhat are the Variables in Your Experiment?Experiment? Varying the route is theVarying the route is the independent variableindependent variable The time it takes is theThe time it takes is the dependent variabledependent variable Keeping the same walkerKeeping the same walker throughout makes the walker athroughout makes the walker a control variable.control variable.
- 18. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 18 DataData Based on Observations Observations are based on the five senses See, hear, feel, taste, smell
- 19. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19 2 Types of Data Quantitative: measurements (think: quantity) Qualitative: only observational but not measureable
- 20. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 20 Data Inferences DO NOT belong in observations Inferences are opinions, judgements, ideas or thoughts about observations
- 21. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 21 DataData Must be organized Can be organized into charts, tables, or graphs
- 22. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 22 ConclusionConclusion A ConclusionConclusion is a statement based on the data of the experiment. The conclusion may or may not support the hypothesis. The answer to the hypothesis based on the data obtained from the experiment
- 23. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 23 Write the following in your notes: Identify the following for each scenario (1st or Smithers scenario is an Example): 1. Problem 2. Hypothesis 3. Control Group 4. Experimental Group 5. Independent Variable 6. Dependent Variable 7. Constants 8. What should the conclusion be? 9. Is the data quantitative or qualitative?
- 24. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24 Smithers thinks that juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the juice to drink while they work. Group B is not given the juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.
- 25. Smithers Scenario Answers 1. Problem Will drinking juice increase the worker’s productivity? 2. Hypothesis Drinking juice will increase productivity 3. Control Group: Group B 4. Experimental Group: Group A 5. Independent Variable: The Juice 6. Dependent Variable: Increase or Decrease Productivity 7. Constants: # of workers (both 50 workers and task (stapling papers) 8. What should the conclusion be? That the juice was not effective in increasing productivity 9. Is the data quantitative or qualitative? Quantitative Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 26. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 26 Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of "treatment" there is no change in the appearance of the green slime on either side of the shower.
- 27. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 27 Bart believes that mice exposed to microwave rays will become extra strong. He decides to perform this experiment by placing 10 mice in a microwave for 10 seconds. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. he found that 8 out of 10 of the microwaved mice were able to push the block away. 7 out of 10 of the non-microwaved mice were able to do the same.
- 28. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 28 Krusty was told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes.
- 29. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 29 The Strange Case of BeriBeri In 1887 a strange nerve disease attacked the people in the Dutch East Indies. The disease was beriberi. Symptoms included weakness and loss of appetite, victims often died of heart failure. Scientists thought the disease might be caused by bacteria. They injected chickens with bacteria from the patients blood. The injected chickens became sick. However, so did a group of chickens that were not injected with bacteria.
- 30. Copyright@ McGraw-Hill Companies, Inc. Permission required for reproduction or display. 30 New observation/hypothesis One of the scientists, Dr. Eijkman, noticed something. Before the experiment, all the chickens had eaten whole-grain rice, but during the experiment, the chickens were fed polished rice. Dr. Eijkman researched this interesting case. he found that polished rice lacked thiamine, a vitamin necessary for good health.