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Scientific Method. A logical method of problem solving. Steps of the Scientific Method. Making observations that lead to a question . Forming a hypothesis to answer the question . Testing the hypothesis by experimentation .
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Scientific Method A logicalmethod of problem solving
Steps of the Scientific Method • Making observations that lead to a question. • Forming a hypothesis to answer the question. • Testing the hypothesis by experimentation. • Making a conclusion based on the results of the experiment.
Definitions: • Observing: Use of the senses and devices in the lab to obtain information. • Conclusion: A statement based on observations and prior knowledge.
Label each of the following as an Observation or Conclusions • The milk tastes sour. • The sour milk must be spoiled. • The temperature of liquid is 33oC. • The wire must be made of copper because of its color. • It must be about to rain because the sky is getting dark. • When powder is added to water, it fizzes. • The gas blown on the candle must be CO2 because the flame went out. • Lemon juice is an acid and tastes sour. All acids must taste sour.
Check Your Answers • The milk tastes sour.O • The sour milk must be spoiled.C • The temperature of liquid is 33oC.O • The wire must be made of copper because of its color.C • It must be about to rain because the sky is getting dark.C • When powder is added to water, it fizzes. O • The gas blown on the candle must be CO2 because the flame went out.C • Lemon juice is an acid and taste sour. All acids must taste sour.C
Step 1: Observations • 1. Quantitative: Includes numbers and units. Ex. 100oC • 2. Qualitative: Does not include numbers and units. Ex. Hot
Scientific Method Candle Lab • Get in a group of 4 people and title one sheet of notebook paper as above. Put all group members names on the top of the paper • Supplies: Each group will need a candle, ruler, matches, and balance
Scientific Method Candle Lab • Write down the word Observations: and number 1-8. • Using complete sentences, make 8 observations before, during, and after lighting a candle. Allow the candle to burn for 5 minutes. Be sure to include quantitative and qualitative observations. • Using your observations, draw a conclusion.
Circle any of the observations that match yours and label as Qual(L) or Quantit(N) observations on notes • The candle is white. • The candle is shaped like a cylinder. • This candle has a diameter of 2.1 cm. • The candle’s material smells like wax. • The candle material is soft enough to be scratched. • The candle is lit by holding a flame close to the wick. • The flame is about 2 cm tall and 1 cm wide. • After the flame goes out, the liquid solidifies after 5 seconds.
Check your answersL=QualitativeN=Quantitative • The candle is white.L • The candle is shaped like a cylinder.L • This candle has a diameter of 2.1 cm.N • The candle’s material smells like wax.L • The candle material is soft enough to be scratched.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
Step 2: Hypothesis: an educatedguess A good hypothesis: • Explains an observation. • can be tested • will predict an outcome
Scientific Method Candle Lab Write down the word Hypothesis: on your lab sheet Form a hypothesis for each question: • What is the purpose of the candle’s wax? • As the candle burns it gets shorter. Where does the wax go?
Step 3: Experiment: • is designed to test a hypothesis. • involves variables • is performed under controlled conditions Variables: factors that can be changed. Control: a variable that is held constant
In a good experiment: • only twovariables are allowed to change. • the manipulated(orindependent) variable is changed by the scientist. • the responding (or dependent) variables changes as a result of the experiment. • all other variables are controls because they are held constant.
Step 4: Conclusion: • the final step of the scientific method made from the results of an experiment.
Scientific Method Candle LabWrite down the words Experiment and Conclusion: on your lab sheet Test the hypothesis you formulated for the purpose of the candle’s wax. • Obtain a piece of cotton string to simulate the wick. Holding the wick with a forcep, light the string and observe. • Was your hypothesis correct? Formulate a conclusion based on your observation about the purpose of the candle wax.
Scientific Method Candle Lab Test the hypothesis you formulated for where the wax goes as the candle burns. • Record the mass before and after burning a candle for 5 minutes or find a group that recorded mass as an original observation. • Was your hypothesis correct? Formulate a conclusion based on your observation about what happens to the wax.
