Scientific Method A logical method of problem solving

Scientific Method • A logical method of problem solving a. b. c. d. Steps of the Scientific Method Making observations that lead to a question Forming a hypothesis to answer the question Testing the hypothesis by experiment 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. 2. 3. 4. 5. 6. 7. 8. The milk taste sour. O The sour milk is spoiled. C The temperature of the liquid is 33°C. O The wire is made of copper because of its copper color and it conducts electricity. C It is about to rain because the sky is dark. C When the powder was added to water, it fizzed. O The gas blown on the candle was CO 2 because the candle went out. C Lemon juice is an acid and taste sour. All acids must taste sour. C Episode 101

Observations • Quantitative – Includes numbers and units • Qualitative – Does not include numbers and units – Depends on senses 1. 2. 3. 4. 5. 6. 7. 8. Candle is white. L It is shaped like a cylinder. L The candle is 2. 1 cm in diameter. N The candle material smells like wax. L The candle material is soft enough to be scratched by a fingernail. L The candle is lit by holding a flame close to the wick. L The flame is about 2 cm tall and 1 cm wide. N After the flame goes out, the liquid solidifies after 5 seconds. N 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