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Graphing Tips
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Graphing Tips
This project lends itself well to graphing. Graphing allows scientists to see relationships between numbers. Graphs are used to show how a variable changes over time, show trends in data clearly (i.e. they visibly show how one variable can change as the other increases or decreases), and enable the viewer to make predictions about the results of data not yet recorded. A typical graph has an x-axis (horizontal) and a y-axis (vertical). In Lesson 4, students will utilize temperature and precipitation data and create Bar, Line, and Pie graphs.
  1. Bar Graphs: Bar graphs are used to compare data. They are good for plotting data and illustrating how something changes over time (days, months, years, etc.) and are also used to illustrate to two compare different items. The x-axis (horizontal) is typically used to identify the time period and the y-axis (vertical) displays the numbers for the amount of item measured (temperature, precipitation, etc.).
    • Precipitation(C) over Time (1 year) of 1 city: sample
    • Temperature (C) over Time of 1 city: sample
    • Comparison Bar Graph - Precipitation (mm) of 2 or more cities over Time (date): sample
  2. Line Graphs: Line graphs show gradual changes in data. Line graphs are also good for summarizing the relationship between two pieces of information and how they depend on each other.
    • Temperature (C) over Time (date): sample
    • Temperature (C) over Time (date) of 2 or more cities: sample
  3. Combination Chart: Bar and Line Graph: A comparison chart displays two graphs on the same graph.
    • Temperature (C) and Precipitation (mm) over Time (1 year) of 1 city: sample
  4. Circle Graph: A circle graph, or pie chart, is a circle divided into various parts to identify different percentages of an item as part of a whole. For example, the bigger the percentage of a part, the bigger that part occupies of the circle.
  5. Scatter Plot: Scatter plots demonstrate a trend in the data and are similar to line graphs in that they begin by plotting different data points. However, the difference is that each of the individual points are not connected together with a line but rather a trend line is added where approximately the same number of points occur below the line as above it.
    • Temperature (C) vs. Elevation (m): sample

Note: It is important to be aware of how graphs and charts can be altered (skewed), because the user could be easily misled and create inaccurate conclusions. Altering graphs can occur purposely or accidentally. Graphs can be altered several ways including the practice of not using consistent scales on the axes, meaning that the values between each point along the axis are not consistent. You should keep this in mind while the students are creating the graphs.

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