Graphing / Using Graphs• To illustrate what happens during the

course of an experiment is done with a graph.

• Graph = a visual display of information of data.

• Slope = steepness, the ratio of vertical to horizontal change

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Slope=Rise Run

Rise = change in “y” (vert.) axis/variable

Run= change in “x” (horz.) axis/variable

Ratio of vertical change : change horizontal

Dependent and Independent Variables• Manipulated or Independent variable = causes a

change in the other variable. ****Y axis/vertical axis****

(length of time, speed)

• Responding or Dependent variable = a factor whose value changes or depends upon the value of the manipulated/ independent variable.

****X axis/ horizontal **** (amount of temperature, damage)

Independent Variable

X Axis

Dependant Variable Y Axis

Line Graphs• Line graphs are used to show trends

or how the data change over time.

• Adjacent points are related with a straight or curving line.

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Line Graphs• The dependent variable is plotted on the

vertical y-axis.

• The independent variable is plotted on the horizontal x-axis.

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Time

Temperature

Graphs Show Change

• In Figure 2-10, two things are changing, or varying – time and temperature.

• Time the independent variable. Its value does not depend on changes in the other variable, temp.

• Temperature is the dependent variable. Its value depends on changes in time.

A bar graph is used for comparing information collected by counting

Bar Graphs• A bar graph is useful for comparing

information collected by counting.

• In a bar graph, the bars are not connected.

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Circle Graphs• Circle or Pie Graphs show how a fixed quantity is broken down into parts.

• The circle represents the total. The slices represent the parts as percentages.

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SI Use in the U.S.

• Where do we use SI other than in science??

Athletics = metersMedicine = mg. & ml.Soft drinks = L

Benefits

• Easy to convert powers of 10

• One time cost

• Ready for trade to other countries