Using a Scientific Approach

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Using a Scientific Approach

• Unit 3.1

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Why We Need A Methodical Approach To Science

• Albert Einstein once said
• "Two things are infinite the universe and human
  stupidity, and I'm not sure
• about the universe."
• Never a truer word was said!

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Alchemy ? Chemistry

• Transformed chemistry from a science of
  observation to a science of measurement

Lavoisier
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Scientific Method

• An organized plan for gathering, organizing, and
  communicating information
• To solve a pressing problem
• To understand an observed event

Scientific Method Scientific Method Goals
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Why the scientific method?

• The real purpose of the scientific method is to
  make sure Nature hasn't misled you into thinking
  you know something you don't actually know.
• Experiments considered to be failures
• Flight Wright brothers failed many times
• Light bulb - gt1000 filaments tried by Edison
• Sticky pads from a botched experiment at 3M
• Failure is part of the Method ... embrace it!

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Make Observations
Ask Questions?
Background Research
Construct Hypothesis
Design/Perform Experiment
Analyze Data
Hypothesis Correct
Hypothesis Wrong
Report Results
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Make an Observation

• Using your senses ...
• Stars in the heavens move (some faster than
  others!)
• Heart pumps faster when I run
• Ocean tides vary
• Earthquakes destroy things
• Chemicals react
• Living things reproduce die

Step 1 Make An Observation
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Ask Questions?

• Who, What, When, Where, Why, or How?
• Ask questions that can be answered with a
  quantitative measurement

Step 2 Ask Questions
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Background Research

• Dont reinvent the wheel!
• Use available research methods to see if the
  question has already been answered
• Internet
• Scientific Journals
• Peer Conferences
• Familiarize yourself with the facts.

Step 3 Background Research
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Construct Hypothesis

• An educated guess to a question that is
  verifiable (could be right or wrong)
• If I _____, then _______ will happen
• ______ will occur because _______
• Examples
• If I sail west I will fall off the earth
• The polar ice caps will melt if ozone is depleted
  
• Silver is a good light bulb filament because ...

Step 4 Construct Hypothesis
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Design Experiment

• Design with purpose, intent
• Variable that causes a change in another
• Variable that changes in response to the
  manipulated variable
• Experiment in which only one variable, the
  manipulated variable, is deliberately changed.

Step 5 Design Experiment Manipulated Variable
(independent) Responding Variable (dependent) C
ontrolled Experiment
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Perform Experiment

• e.g. Emc2
• (we cant change energy into mass)
• Historical data
• (an earthquake caused Mt. Vesuvius to erupt and
  destroy Rome)
• When designing an experiment, be careful NOT to
  introduce opinion/slant
• During an experiment be careful NOT to rule out
  extraneous data. You MUST explain it!
• More trial runs more accurate data

Some hypothesis cant be tested Bias Extrane
ous Data
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Analyze Data Draw Conclusions

• Interpret what the data truly says
• (Your seeking the TRUTH)
• Dont attempt to make the data fit your
  hypothesis
• e.g. geocentric vs. heliocentric models
• Stick to standard deviations when feasible

Step 6 Analyze Data Draw Conclusions
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Scientific Method Approach 1

• Observe car wont start
• Ask Is it the battery connections?
• Background Research Experience tells you this
  could be a possible cause
• Hypothesis If I clean the connections the car
  will start
• Experiment Clean battery connections with coke
  and try starting car
• Data Car engine wont turn over
• Hypothesis failed repostulate hypothesis

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Scientific Method Approach 2

• Observe internet connection failed during
  lightning storm
• Ask Is the problem with my computer or
  BellSouths connection?
• Background Research Experience tells you either
  could be a possible cause
• Hypothesis If I reboot my router I will restore
  the connection
• Experiment You reboot the router and wait
• Data Internet connection restored
• Hypothesis correct, problem solved

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Problem Solving in Chemistry

• Analyze
• Calculate
• Evaluate

Determine What do you know? What are you
asked to find? Statistical Analysis, are units
correct? Does the answer make sense?
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Equipment in Chemistry

• Beaker Flask

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Equipment in Chemistry

• Different Types of Flasks

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Equipment in Chemistry

• Graduated Cylinders

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Equipment in Chemistry

• Test Tube Titration