GraphingGraphing

GraphingGraphing

Graphs are a useful tool in Graphs are a useful tool in science.science.

The visual characteristics of a The visual characteristics of a graph make trends in data easy to graph make trends in data easy to see. see.

One of the most valuable uses for One of the most valuable uses for graphs is to "predict" data that is graphs is to "predict" data that is not measured on the graph.not measured on the graph.

Three Basic Graph Three Basic Graph Types Types

Line GraphLine Graph

Bar GraphBar Graph

Pie GraphPie Graph

A A Line GraphLine Graph best best represents represents “change “change

over time” over time” data.data. Results

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A A Bar GraphBar Graph should should be used for be used for “one-“one-

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A A Pie GraphPie Graph can can clearly display clearly display

percentages or “parts percentages or “parts of a whole”.of a whole”.

Graphing StepsGraphing Steps

Identify the Identify the VariablesVariablesIndependent Variable - Independent Variable -

(the thing you changed) (the thing you changed) Goes on the X axis Goes on the X axis

(horizontal) (horizontal) Should be on the left side of Should be on the left side of

a data table.a data table.

Dependent Variable - Dependent Variable - (changes with the independent (changes with the independent variable) variable) Goes on the Y axis (vertical) Goes on the Y axis (vertical) Should be on the right side of Should be on the right side of

a data table. a data table.

ScaleScale

Determine a scale:Determine a scale:the numerical value for the numerical value for each square.each square.

Spread the graph to use Spread the graph to use MOST of the available MOST of the available space.space.

Label Axis'sLabel Axis's

You need to tell everyone You need to tell everyone reading your graph what the reading your graph what the graph means.graph means.

Be sure to include units.Be sure to include units.

PlottingPlotting

Plot each data value on the graph Plot each data value on the graph with a dot. You can put the data with a dot. You can put the data number by the dot, if it does not number by the dot, if it does not clutter your graph.clutter your graph.

DrawingDrawing

Draw a curve or a line Draw a curve or a line that best fits the data that best fits the data points. points.

Most graphs of Most graphs of experimental data are experimental data are not drawn as "connect-not drawn as "connect-the-dots".the-dots".

Title & KeyTitle & Key

Your title should clearly tell Your title should clearly tell what the graph is about.what the graph is about.

If your graph has more than If your graph has more than one set of data, provide a one set of data, provide a "key" to identify the different "key" to identify the different lineslines