P3.2 Scientific Methods


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P3.2 Scientific Methods

  1. 1. Write and answer the following question.  How can you prove that the world is not flat?
  2. 2. Objectives: 1. Explain what scientific methods are. 2. Explain how scientific methods are used to answer questions. 3. Describe how a hypothesis is formed and tested. 4. Identify methods that are used to analyze data. 5. Explain how a conclusion can support or disprove a hypothesis. 6. List methods of communicating data.
  3. 3. What are Scientific Methods? The ways in which scientists answer questions and solve problems. ○ As scientists look for answers, they often use the same steps. But there is more than one way to use the steps. ○ Scientists may repeat some steps or do them in a different order.
  4. 4. Ask a Question  Helps focus the purpose of an investigation.  Scientists often ask a question after making observations.  Observation  any use of the senses to gather information. ○ Should be accurately recorded so that scientists can use the information in future investigations.
  5. 5. A Real-World Question  Engineers are scientists who put scientific knowledge to practical human use.  Engineers create technology.  Technology  Application of science for practical purposes. ○ For example, engineers Czarnowski and Triantafyllou studied the efficiency of boat propulsion systems.
  6. 6.  The Importance of Boat Efficiency  Efficiency compares the energy used to move the boat forward with the energy supplied by the engine.  Making boats more efficient would save fuel and money.  Based on their observations  Czarnowski and Triantafyllou asked the question: ○ How can boat propulsion systems be made more efficient?
  7. 7. Form a Hypothesis  Once you have asked a question and made observations, you are ready to form a hypothesis.  Hypothesis  Explanation that is based on prior scientific research or observations that can be tested.
  8. 8.  Nature Provides a Possible Answer  Czarnowski studied penguins swimming and formed the hypothesis: ○ A propulsion system that mimics the way a penguin swims will be more efficient than a propulsion system that uses propellers.  Make Predictions  Before scientists test a hypothesis ○ They often make predictions that state what they think will happen during the actual test of the hypothesis. Make a prediction for these images.
  9. 9. What is a Ratio?  Take out your Ratio worksheet from yesterday and compare your answers with a partner.
  10. 10. Test the Hypothesis  After you form a hypothesis, you must test it.  Testing helps you find out if your hypothesis is correct or not.  Keep It Under Control  One way to test a hypothesis is to do a controlled experiment. ○ Tests one variable at a time. ○ By changing only that variable, scientists can see the results of just that one change.
  11. 11.  Testing Proteus  Czarnowski and Triantafyllou built a model penguin boat called Proteus to test their hypothesis.  The engineers took Proteus into open water to collect data.  Data ○ Pieces of information acquired through observation or experimentation Day Height (cm) Cup 1 1 0.5 Cup 2 2 1.0 Cup 3 3 1.7 Plant Growth with Sunlight
  12. 12.  Analyze the results:  Once you have your data, you must analyze them to find out whether the results support your hypothesis.  The graphs below show the analysis of the tests done on Proteus.
  13. 13. Draw Conclusions  At the end of an investigation  You must draw a conclusion. ○ It can help you decide what you do next.  The Proteus Conclusion  Czarnowski and Triantafyllou found that the penguin propulsion system was more efficient than a propeller system. ○ So, they concluded that their hypothesis was supported.
  14. 14. Communicate Results  One of the most important steps in an investigation is to communicate your results accurately and honestly.  Communicating About Proteus  Czarnowski and Triantafyllou published their results in academic papers.  They also displayed their project and its results on the Internet.