Write and answer the following question.

How can you prove that the world is not flat?

3.2 - SCIENTIFIC METHODS

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.

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.

Ask a Question Helps focus the purpose of an investigation.

Scientists often ask a question after making observations.

Observationany use of the senses to gather information.

○ Should be accurately recorded so that scientists can use the information in future investigations.

A Real-World QuestionEngineers 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.

The Importance of Boat EfficiencyEfficiency 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?

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.

Nature Provides a Possible AnswerCzarnowski 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 PredictionsBefore 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.

What is a Ratio?

Take out your Ratio worksheet from yesterday and compare your answers with a partner.

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 ControlOne 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.

Testing ProteusCzarnowski 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

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.

Draw Conclusions At the end of an investigation

You must draw a conclusion. ○ It can help you decide what you do next.

The Proteus ConclusionCzarnowski and Triantafyllou found that the

penguin propulsion system was more efficient than a propeller system.○ So, they concluded that their hypothesis was

supported.

Communicate ResultsOne of the most important steps in an

investigation is to communicate your results accurately and honestly.

Communicating About ProteusCzarnowski and Triantafyllou published their

results in academic papers.They also displayed their project and its results

on the Internet.