What is a source of error

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					                                  What is a source of error?                                                              Use of Scientific Language in Writing
                                                                                                Keep this sheet for reference. Use for all lab write-ups, as well as when responding to
When asked to find a source of error, you are searching for likely causes of inaccurate,        questions on quizzes, tests or the exam.
imprecise and/or inadequate results that were beyond your ability to control.
                                                                                                   Colloquial or Slang Expressions often            Equivalent (if applicable) of proper
       Potential Sources of Error                           Not a Source of Error                    used by teachers and students when            formal writing appropriate to science
(variables beyond your control that have             (variables within your control or               speaking or in informal writing (ex.                 reports or test papers
       appreciable effect on data)                      variables that do not have an                               novels).
                                                         appreciable effect on data)                INAPPROPRIATE IN SCIENTIFIC
- limitations of equipment/tools, i.e.          - improper measurement taken due to                               WRITING
centigram balance can weigh only to the         carelessness or lack of knowledge of how        ...a lot of copper (II) sulfate was needed.      …a considerable amount of copper (II)
nearest 0.01g                                   to read the equipment (solution: re-do lab)                                                      sulfate was needed.
                                                - the fact that when requested to add 10mL                                                       (“a lot” is informal/ colloquial)
                                                of a substance, some students may add           We then mix the solution.                        The solution was mixed.
                                                9mL, and others 8mL                             I thought the lab was pretty poorly              The design of the lab experiment was
                                                - the fact that if requested to use ~2g (to     designed.                                        inadequate because…
                                                0.01g) of a substance, one student                                                               (“pretty” is colloquial. Your “thoughts”
                                                accurately masses 2.38g and another                                                              must be justified.)
                                                accurately masses 1.53g.                        I thought the lab was pretty good.               The lab performed successfully verified
                                                - dirty glassware (solution: re-do with clean                                                    the law of conservation of mass.
                                                glassware)                                      Then u add the salt.                             *** Use of internet chat slang
- limitation of the procedure. The procedure    - procedure followed incorrectly (solution:                                                      inappropriate.***
makes an assumption which is not entirely       re-do lab)                                                                                       Instead: The salt was added.
true (i.e. the procedure may assume that all                                                    I liked the lab. It was fun. I learned a lot.    Inappropriate for lab.
product of a reaction is being massed, when                                                     The lab shows that science can be fun and
some inevitably escapes)                                                                        educational at the same time.
- the procedure assumes a condition which                                                       People didn’t always care about emissions.       Emissions were not a concern throughout
is not entirely true                                                                                                                             much of history.
- purity of reagents (i.e. chemicals) used.     - variables out of your control that usually                                                     *** Do not use CONTRACTIONS (ex.
Note: usually this is not the major source of   have no appreciable effect on the data (ex.                                                      didn’t, couldn’t, hasn’t).
error in high school labs and should not be     a small room temperature fluctuation from       “What is ecology?” you may ask. I will tell      Ecology is the study of….
stated                                          the time you started to the time you            you.                                             *** Rhetorical questions or “attention
- non-calibrated thermometer or other           finished the lab, usually the purity of                                                          grabbers” used in stories/novels
instrument that is providing you data that      reagents, position changes of stars in the                                                       inappropriate in science.
effects the quality of the result               sky)
                                                                                                      In the body of your document                   At the end in a separate Reference
In lab write-ups:                                                                               ex. – part of introduction section of lab        ex. – part of reference section at back of
      State the source of error                 explicitly explain how result is effected      Introduction
                                                                                                    Ecology is the study of how all              References
                                                                                                organisms, including plants, animals,
                                                                                                insects and microbes function and interact       Wilkinson, John; Jeffreys, Donald;
                                                                                                in their environment (Wilkinson et al.). It is   Williams, Sue. Principles of Ecology.
                                                                                                important to understand ecology in a time        Nelson Publishing, 2003.
                                                                                                when the earth is experiencing many
                                                                                                environmental problems (Wilkinson et al.).

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