Scientific Method In Chemistry

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Scientific MethodIn Chemistry

• Mr. Barner

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For all Lab Report

• Written in complete sentences and paragraph form
  where appropriate.
• NEAT LISTS are OK
• Use appropriate grammar (no spelling or
  punctuation errors).
• Do not use Pronouns (NO PP WORDS).
• Only appropriate abbreviations (mL, C).
• Written in your own words.
• Include a Title describing the lab.

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Problem/Purpose

• Problem is written in question form.
• Purpose is written in statement form.
• Both must be testable.
• Question to be examined is clearly stated and
  reflects the variables.

4
Background Information

• Neat and Organized
• Any Initial Observations
• Concepts to be considered
• key word definitions, formulas, any relevant
  information
• Dependent and Independent variables are
  identified with units.
• Any Math expected
• equations, conversions (1000 g 1 kg)

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Hypothesis

• A statement answering the problem of what to
  expect.
• Worded similar to the problem.
• Considers just how great an expectation.
  (NUMBERS)
• Not enough to say one variable will effect another

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Materials

• All important equipment and materials are listed.
• Include amounts of each material/substance.
• Include sizes of equipment
• (Ex 250mL Beaker).
• Include a DIAGRAM to show setup/measurements
• Include Labels of Items drawn

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Procedures

• Procedure is in specific and clear steps.
• It is written well enough that the experiment
  could be duplicated.
• Include how much to measure out
• Include how many trials (REPEAT AMOUNTS)
• Include how to vary the independent variable
• (REPEAT STEPS)

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Observations

• Qualitative Observations
• Any thing that describes the objects and what
  happens
• Quantitative Observations
• Any measurements, counting
• May be in data table format
• DO NOT include any calculations

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Calculations

• Any math needed to determine values
• Subtracting paper mass from total mass
• Only need one sample from each type of
  calculation
• One for subtracting masses
• One for finding density
• INCLUDE UNITS

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Data Table

• Title that reflects the data.
• Separate data into groups and make each group its
  own column.
• The top of each column must be labeled include
  units if applicable.
• May include results of calculations.
• Includes data that used in graph

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Graph

• Title that reflects data
• Increments start at zero and spacing is equal and
  represents the ENTIRE RANGE of data.
• Independent and dependent variables are on
  appropriate axis.

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Graph

• Includes labeling of axis with correct units.
• Data in graph(s) correspond with data table(s).
• Draw a line of best fit or the appropriate
  curve that demonstrates the relationship of the
  graph.

13
Graph Analysis

• Determine Slope of Trend Line
• Draw a large triangle
• Find the RUN of the triangle
• Find the RISE of the triangle
• Find the RISE/RUN Slope
• Determine Y-Intercept when Independent Variable
  is 0

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Graphical Analysis

• 5 test
• Determines importance of y-intercept
• Find maximum y-value measured
• Divide y-intercept by max y-value
• If greater that 5 then intercept is significant
  (gt5 KEEP)
• If less than 5 then intercept is not significant
  and can be ignored
• (lt5 DROP)

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Graphical Analysis

• Determine Math Model of Trend Line
• Dep. Var. (slope) Ind. Var. intercept
• y (m) x b
• Substitute each variable and value (with units)
  into math model
• Total Mileage (16 miles/1gallon) Fuel used
• Weight of child (2.5 lbs/1month) Age 7 lbs

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Extension

• Class Results
• Overall Models of Variables
• Graph and Math
• New Concepts from the Lab

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Evaluation

• Include percent error and / or percent yield when
  appropriate.
• Percent Error
• (Expected Value Lab Value)/Expected Value
• Percent Yield Lab Value/Expected Value
• Sources of error
• may include execution of experiment, equipment,
  design or organization of lab, and accuracy and
  precision.
• Listing of human error is not acceptable.
• Improvements that could be made to obtain more
  accurate results.

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Conclusion

• What was learned in this lab?
• Include evaluation of hypothesis
• Include overall results
• What evidence supports the lessons learned?
• Sample Data
• Type of graph and slope
• Specific math model for the lab

DO NOT SIMPLY STATE In this lab the hypothesis
was !