Reporting on a Science Investigation

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Reporting on a Science Investigation

• How to write a lab report
• by Mary Ellsworth

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Parts of a Lab Report

• Introduction Problem and Hypothesis
• Procedure Equipment and Method
• Data
• Analysis
• Conclusion
• Discussion of the results

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Example A Pendulum Investigation

• If you change the length of the string, will it
  affect how fast the pendulum swings?

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Create an informative title

• The title tells the reader what the lab is about.
• Be specific
• Science titles tend to be long!

• My Lab Report
• Science Investigation
• Pendulum Lab
• Investigating Pendulum Swings and String Length

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Introduction

• Problem
• a clear statement of your research question
• background information
• discussion to put your question in context
• Definitions

• Hypothesis
• Sets conditions
• Use If.then
• Predicts results
• Is testable

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State the Problem

• Problem If you change the length of the string
  on a pendulum, will it change how fast the
  pendulum swings?

• Problem In this lab we are investigating the
  relationship between the length of a pendulum
  string and the rate of the swings. We are
  studying pendulums in order to demonstrate our
  investigation skills. Our question is, if you
  change the length of the pendulum string, how
  will it change how fast it swings? Fast means
  more swings per 10 seconds. Slow means fewer
  swings.

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Writing a hypothesis

• I think the pendulum will be faster.
• In a smaller distance the pendulum will travel
  back and forth faster and shorter.
• The short string will not continue to swing back
  and forth for as long as the long swing.
• The pendulum will swing back and forth. The
  long string many change fast.

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Writing a hypothesis

• I think that the longer the string is, the
  lesser number of swing it will make in 10
  seconds, because it is easier to travel quickly
  in small spaces than large space, so the string
  will have an effect.
• If it is easier to travel quickly across small
  spaces, then the pendulum will swing faster on a
  shorter string.

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Procedure

• Method
• explains the steps you took to investigate your
  question
• - describes time period, location, details,
  etc.
• Its replicable - someone else could repeat it
  exactly
• write it in past tense

• Equipment materials
• a list of equipment or materials you used
• how many, what size
• describe any special equipment used
• a drawing of how the equipment was set up

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Equipment Materials

• A metal washer
• String
• Measuring tape
• Scissors or small knife
• Timing device

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Equipment Materials

• One 1 metal washer
• Cotton string
• 10cm, 30cm, 45cm, 60cm, 80cm lengths
• A metric measuring stick
• Scissors
• The classroom clock

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Experimental Method

• Look at the lab directions

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Experimental Method

• 1. Construct a pendulum system out of the
  string and a metal washer.
• 2. Test how many full swings the pendulum will
  make in 10 seconds.
• 3. Make a table to show the results of your
  pendulum tests.
• 4. Use a piece of graph paper to make a line
  graph.

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Experimental Method

• Arthur and I measured strings (10, 40, 45, 60
  and 90cm). We tied each string to a metal
  washer. We each took turns to see how many full
  swings it will take in 10 seconds. One of us did
  the swinging, one of us watched the clock. We
  started the pendulum by holding the string out
  horizontally and dropping the washer. We counted
  each back and forth as one full swing.
• (continued)

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Show special equipment or a method

• Here is how we started
• the pendulum.

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Data

• Data table
• Be organized!
• Write numbers neatly and clearly
• Repeat the tests - do at least 3 trials
• Graphs
• - x and y axis with clear labels
• - show the units
• - include a title

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Poorly organized data

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Unlabeled Data

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Clear and organized data

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Analysis

• summary of the data in words
• Highs, lows, trends or any patterns you notice
• Include UNITS on all measurements.
• cm, m, sec, hrs, kg, g,
• explain any mathematics that you used
• Added, Subtracted, Calculated averages,
• Equations
• Choose appropriate graph type
• Line, bar, pie chart
• uncertainties accuracy of your measurements

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What problems do you see?
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Example of a graph

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What problems do you see?
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What problems do you see?
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Conclusion

• Restate your hypothesis for this lab
• Decide
• The data ________________ my hypothesis.
• (supports, does not support)
• Tell the conclusions you reached about your
  research question
• Generalize What is the general principle
  involved?

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Writing a Conclusion
Our hypothesis was right.
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Writing a Conclusion

• Carol and I were right. The smaller strings
  took more swings than the larger strings did.

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Writing a Conclusion

• Our hypothesis for this lab was that the longer
  string would swing more slowly than the shorter
  string.
• The data supports our hypothesis. We found the
  longer the string had fewer the swings in 10 sec
  (slower). In general, the longer the string, the
  slower the pendulum swings

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What if your hypothesis is NOT supported?

• My hypothesis was wrong!
• Throw out the whole experiment!!

The data did not support my hypothesis but I
learned that . which means that Next I would
like to try.
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Discussion of the Results

• Put your conclusions in context.
• How do the results relate to the larger picture?
• Discuss the strengths and weaknesses of your
  method
• What problems did you have?
• What could you do to extend or improve your
  research (a new question)?

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Discussion of the results

• Refer to specific data. Refer to the graph.
• - The graph shows.
• Use language that describes change.
• The number of swings decreased.
• As string length increased, of swings
  decreased.
• The graph shows that the number of swings
  increased as the string length decreased.
• String length and of strings are inversely
  related.

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a new question
If we used larger washers, what results would we
get? What would happen if we did not hold the
pendulum in our hand - did we unconsciously
influence it? Would the results be the same if
we did a 360 deg full swing?

• Why did this happen?
• What if the wind blew on it, would it be the
  same?

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Report Format

• Use headings
• For a formal lab report, include a cover page
• Include the date
• Report should be neat and well organized.
• (Typed)

Introduction In this report we investigated
how the length of the pendulum string is related
to the number of swings Etc. Procedure We
tied a washer to each length of string and held
it so it could swing back and forth. Etc. Data
length of swings
10 - 20 15 - 15
30 - 10 Analysis Look a the graph
of our data. Etc Conclusions Our
hypothesis for this lab was that the shorter
string would swing faster. The data supports
this hypothesis. Etc. Discussion of the Results
We noticed that the pendulum was swinging
much slower when the string was longer. Etc.
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Departing thoughts

• "Today, we benefit tremendously from the records
  of accomplishments and failures of people who
  have come before us.
• The people who took the time to accurately record
  their efforts, decisions, measurements, tests and
  conclusions are the same people who will live
  forever in their records and will serve as
  guides for future generations. "
  - Dr. H. David
  Snyder, Gallaudet University
• Remember the Basques!
• - Ms. Mary
  Ellsworth, MSSD

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The End!

• THE SLEUTH