Scientific Method• A logical method of problem solving

Steps of the Scientific Methoda. Making observations that lead to a

questionb. Forming a hypothesis to answer the

questionc. Testing the hypothesis by experimentd. Making a conclusion based on the results of

the experiment

Episode 101

Definitions• Observing: Use of the senses and devices in the

lab to obtain information• Conclusion: A statement based on observations

and prior knowledge

1. The milk taste sour.2. The sour milk is spoiled.3. The temperature of the liquid is 33°C.4. The wire is made of copper because of its copper color and it

conducts electricity.5. It is about to rain because the sky is dark.6. When the powder was added to water, it fizzed.7. The gas blown on the candle was CO2 because the candle went

out.8. Lemon juice is an acid and taste sour. All acids must taste sour.

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Episode 101

Observations• Quantitative – Includes numbers and units

• Qualitative – Does not include numbers and units– Depends on senses

1. Candle is white.2. It is shaped like a cylinder.3. The candle is 2.1 cm in diameter.4. The candle material smells like wax.5. The candle material is soft enough to be scratched by a fingernail.6. The candle is lit by holding a flame close to the wick.7. The flame is about 2 cm tall and 1 cm wide.8. After the flame goes out, the liquid solidifies after 5 seconds.

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Episode 101

Hypothesis• An educated guess• A good hypothesis:– Explains an observation– Can be tested– Will predict an outcome

Practice forming a hypothesis:• What is the purpose of the candles wick?

• As the candle burns, it gets shorter. Where does the wax go?

Episode 101

Experiment• Is designed to test a hypothesis• Involves variables– Factors that can be varied or changed

• Is performed under controlled conditions– Control: a variable that is held constant

Episode 101

In a good experiment:• Only two variables are allowed to

change• The manipulated (or independent)

variable is changed by the scientist

• The responding (or dependent) variable changes as a result of the experiment

• All other variables are controls because they are held constant.

Episode 101

• Design an experiment to test your hypothesis concerning the candle.

• Develop a conclusion from the data and observations made in the experiment.

Episode 101