The Scientific Method

It’s not just for science class.

Everyday Thinking: Refined

• Albert Einstein• “The whole of science

is nothing more than a refinement of everyday thinking.”

You’ve Got QuestionsWe’ve Got Answers

• The Scientific Method is more so “We’ll Get Answers”

• Key point:Scientific Method is not limited to science.

• This is a problem solving approach.

• Problems happen everywhere.

Two or Three ThingsAbout Scientists

1. Scientists generally like to divide things into steps or points.

2. Scientists like to make up words to make things sound more complex.

3. Scientists often have weird senses of humor. (unofficial)

Steps of an Experiment

1. Question2. Hypothesis

3. Experiment

4. Data/Results5. Conclusion

So what do these words mean in the real world?

Steps of an Experiment

1. Question2. Hypothesis

3. Experiment

4. Data/Results5. Conclusion

• What do you want to know?• What do you think will

happen?• Set up a test and see what

happens.• Write down what happens.• Explain what happened.

Step-By-Step: Question• “What do you want to

know?”• If you don’t have a

question, you don’t need to make an experiment.

• There are no stupid questions…

• …but some are better for experiments than others.

• The more specific, the better.

Step-By-Step: Question

• Example questions:• What happens when I mix two chemicals

together?• Not very informative

• What happens when I mix an acid with a base?• Getting there, but there are lots of acids and bases to pick

from for an experiment.

• What happens when I mix hydrochloric acid with sodium hydroxide?– Clear and specific. Good job!

Step-By-Step: Hypothesis

• “What do you think will happen?”

• It’s your idea.• It doesn’t matter if it

ends up being right or wrong.

• It’s just your idea.

Step-By-Step: Hypothesis

• Possible hypotheses– The chemicals will form a purple solid.– Nothing will happen.– The chemicals will form water and a salt.

• All good hypotheses that can be observed.– Hamsters will take over the world.

• Not really relevant to the experiment…

• Let’s go with the first one.

The Experiment So Far

• Question: What happens when I mix hydrochloric acid with sodium hydroxide?

• Hypothesis: The chemicals will form a purple solid.

• Experiment: ??• Results: ??• Conclusions: ??

Step-By-Step: Experiment

• The Test• Should be reproducible.• Should isolate one

variable at a time if possible.

• Play it safe. • Don’t take chances.• Must be approved by the

teacher if it is in lab.

Step-By-Step: Experiment

• Pour a small amount of sodium hydroxide into a test tube containing hydrochloric acid.

• We could have been more specific by stating exactly how much of each chemical and how concentrated the chemicals should be.

The Experiment So Far

• Question: What happens when I mix hydrochloric acid with sodium hydroxide?

• Hypothesis: The chemicals will form a purple solid.

• Experiment: Pour a small amount of sodium hydroxide into a test tube containing hydrochloric acid.

• Results: ??• Conclusions: ??

Step-By-Step: Results

• Write down what you observe.

• Be as specific as possible.• Things like colors, shape,

smell, and temperature can all be observed.

• Don’t try to explain your observations, simply write them down.

• Draw pictures if it helps.

Step-By-Step: Results

• The two clear solutions mixed with no visible reaction.

• If you have a thermometer, you could test the temperature.

• If you have pH paper, you could test the pH.

• Results will vary depending on the equipment used as part of the experiment.

The Experiment So Far• Question: What happens when I mix

hydrochloric acid with sodium hydroxide?• Hypothesis: The chemicals will form a purple

solid.• Experiment: Pour a small amount of sodium

hydroxide into a test tube containing hydrochloric acid.

• Results: The two clear solutions mixed with no visible reaction.

• Conclusions: ??

Step-By-Step: Conclusions

• Explain why you think what happened occurred.

• Was your hypothesis proven or disproven?

• Do you need to do additional trials?

• Do you need to do additional experiments?

Step-By-Step: Conclusions

• Start by answering your question if you can.

• Compare those results to your hypothesis.• State any problems that occurred or ways

the experiment could be improved.

The Experiment So Far• Question: What happens when I mix hydrochloric

acid with sodium hydroxide?• Hypothesis: The chemicals will form a purple solid.• Experiment: Pour a small amount of sodium

hydroxide into a test tube containing hydrochloric acid.

• Results: The two clear solutions mixed with no visible reaction.

• Conclusions: Hydrochloric acid and sodium hydroxide do not produce a purple solid when mixed. The chemicals produce a clear solution. Further testing is needed to determine the composition of the final solution.

A Non-Science Example

• Imagine you own a hip and trendy clothing store chain. You currently sell average length shorts. After looking through fashion magazines you see that short shorts are now in fashion. You also know that the dress code at the local high school requires longer shorts.

A Non-Science Example (cont.)

• Your sales manager suggests putting short shorts in store #1, average shorts in store #2, and long shorts in store #3. He says that you could compare sales between stores to see which is the most popular.

• Do you think this is a good plan? Why or why not?

• Can you think of a better plan?

Science Fair

• Each pair will discuss proposed science fair topics and experiments.

• Determine whether the question is a good one for high school students.

• Is it practical?• Is the method reasonable?• Is it an experiment to be proud of at the

science fair?

Homework

• Read Chapter 3 Sections 1 and 2• Revise your science fair ideas if

necessary.