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Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
Objectives
• Explain what scientific methods are.
• Explain how scientific methods are used to answer questions.
• Identify steps in the scientific process.
Unit 1 C-1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
What Are Scientific Methods?
• The ways in which scientists answer questions and solve problems are called scientific methods.
• 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.
Unit 1 Day 1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific MethodsUnit 1 Day 1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
Ask a Question
• Asking a question helps focus the purpose of an investigation. Scientists often ask a question after making observations.
• An observation is any use of the senses to gather information.
• Observations should be accurately recorded so that scientists can use the information in future investigations.
Unit 1 Day 1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
Ask a Question, continued
• A Real-World Question Engineers are scientists who put scientific knowledge to practical human use.
• Engineers create technology. Technology is the application of science for practical purposes.
• For example, engineers Czarnowski and Triantafyllou studied the efficiency of boat propulsion systems.
Unit 1 Day 1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
Ask a Question, continued
• 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?
Unit 1 Day 1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific MethodsUnit 1 Day 1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
Form a Hypothesis
• Once you have asked a question and made observations, you are ready to form a hypothesis.
• A hypothesis an explanation that is based on prior scientific research or observations that can be tested.
Unit 1 Day 1
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Scientific Methods
Form a Hypothesis, continued
• 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.
Unit 1 Day 1
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Scientific MethodsUnit 1 Day 1
Hypothesis
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Visual Concept
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
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. A controlled experiment tests one variable at a time. By changing only the variable, scientists can see the results of just that one change.
Unit 1 Day 1
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Scientific Methods
Test the Hypothesis, continued
• 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 are pieces of information acquired through observation or experimentation.
Unit 1 Day 1
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Scientific Methods
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.
Unit 1 Day 1
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Scientific Methods
Draw Conclusions
• At the end of an investigation, you must draw a conclusion. Your conclusion 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.
Unit 1 Day 1
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Scientific Methods
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.
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