Graphing In Science

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Graphing In Science
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Graphing

• Graphs are a useful tool in science.
• The visual characteristics of a graph make trends
  in data easy to see.
• One of the most valuable uses for graphs is to
  show data collected during an experiment. The
  graph shows your results.

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Why Do We Use Graphs?

• Graphs help us visualize numerical data.
• There are 3 different types of graphs
• Bar graphs
• Pie graphs
• Line graphs

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The cafeteria wanted to collect data on how much
milk was sold in 1 week. The table below shows
the results. We are going to take this data and
display it in 3 different types of graphs.
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Bar Graph

• A bar graph is used to show relationships between
  groups.
• The two items being compared do not need to
  affect each other.
• It's a fast way to show big differences. Notice
  how easy it is to read a bar graph.

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Circle Graph or Pie Graph

• A circle graph is used to show how a part of
  something relates to the whole.
• This kind of graph is needed to show percentages
  effectively.

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Line Graph

• A line graph is used to show change over time.
• It's clear to see how things are going by the
  rises and falls a line graph shows.

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Bar Graph
The same data displayed in 3 different types of
graphs.
Circle (Pie) Graph
Line Graph
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On what day did they sell the most chocolate milk?
a. Tuesday b. Friday c. Wednesday
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On what day was the least amount of chocolate
milk sold?
a. Monday b. Tuesday c. Thursday
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On what day did they have a drop in chocolate
milk sales?
a. Thursday b. Tuesday c. Monday
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OOPS! Wrong Answer
Look for the tallest bar
Try Again
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You are Correct
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OOPS! Wrong Answer
Look for the smallest slice
Try Again
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You are Correct
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OOPS! Wrong Answer
Look for the drop on the line
Try Again
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Choosing the Right Graph

• Use a bar graph if you are not looking for trends
  (or patterns) over time and the items (or
  categories) are not parts of a whole.

• Use a pie chart if you need to compare different
  parts of a whole, there is no time involved and
  there are not too many items (or categories).

• Use a line graph if you need to see how a
  quantity has changed over time.  Line graphs
  enable us to find trends (or patterns) over time.

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Graphing Steps

• Identify the Variables
• Number and label each axis
• Plot the points
• Draw the graph
• Give your graph a title

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Identify the Variables

• Independent Variable - (the thing you changed)
• Goes on the X axis (horizontal)
• Should be on the left side of a data table.
• Dependent Variable - (changes with the
  independent variable)
• Goes on the Y axis (vertical)
• Should be on the right side of a data table.

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Label Axis's

• You need to tell everyone reading your graph what
  the graph means.
• Be sure to include units.

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Title

• Your title should clearly tell what the graph is
  about.
• If your graph has more than one set of data,
  provide a "key" to identify the different lines

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References

• Dorris Spencer
• www.whsd.net/courses/J0077/Unit_01_-_Statistics_an
  d_Data/Bar20Circle20and20Line20Graph20PowerPo
  int.ppt259,1,Different Types of Graphs
• http//www.cobb.k12.ga.us/dickerson/sci20method.
  ppt256,1,Scientific Method