Graphs

Types of

graphs

Line graph

s Sector

graphs

Picture

graphsBar

graphs

Step graph

s

Column

graphs

DIFFERENT TYPES OF GRAPHS

Type of graph Form of information Why they are usedColumn/bar graph

Groups of things that have been measured or counted.

Used to compare things.

Line graph Two quantities that have been measured or counted. One is usually time.

Used to show trends or changes over time.

Pie graph Percentages or proportions of different things that make up a whole.

Used to compare the relative sizes of things.

The main types of graphs used in science are:

Line graphs

The ‘y-axis’

and the ‘x-axis’

Interpreting graphs:In order to interpret a graph there are a number of important parts that you must be able to identify and read. Most graphs will have a:•Title. This gives you a short explanation of what the graph is about.•Horizontal axis. This is a line running across the graph. It has a label beneath it. It may have a scale.•Vertical axis. This is a line running up the side of a graph. It has a label next to it. It may have a scale.•The scales. The scales on horizontal or vertical axes are similar to the scales found on many measuring instruments. A scale is a series of numbers that are increasing or decreasing by the same amount. Part of the skill of interpreting a graph is reading the scales on the axes. Each scale will be labelled with the unit of measurement that has been used.In addition some graphs will have a:•Source. This tells you where the information has come from.• Key. This explains any symbols used in the graph.

Is often used to represent a set of data values

in which a quantity varies with time

Line graphShows how one thing is affected by another.

A line graph is used to show the relationship

between two variables.

A line graph has two lines or axes.

One is the horizontal axis which goes from side to side.

The other is the vertical axis which goes up and

down.

Summary

Things you should follow when drawing a line graph

use graph paperPlot the points accurately with a small dot or

x.

draw in the two axes with a ruler

use a pencil

Line graph

Graph of the effect of temperature on the amount of salt dissolved

Title

Horizontalaxis

Independent variable

Dependent variable

Unit

The scale on the axis is going up by 20

The scale on the vertical axis is going up by 50

Unit Origin

Line graph

Jump= 50Spaces= 2Each line =50/2= 25

Line graphs are useful for showing how things change over time.

Mass depends on the temperature

Temperature does not depend on mass

Vertical axisHorizontal

axis

Jump= 20Spaces= 2Each line =20/2= 10

This table shows the result of Dina’s pulse rate after running in the Junior Quad, measured after each minute. Draw a graph for Dina’s result.

Time Pulse rate(beats per minute)

0 70

1 78

2 97

3 108

4 102

5 87

Example

Time (Minutes)

Puls

e ra

te (b

eats

per

min

utes

)

Graph of pulse rate after exercise

Step 1: draw the axes

Step 2: identify the dependent and the independent variables. (Pulse rate depends on the time so time is the independent and goes on the horizontal axis)

Step 3: draw the axes and label them

Step 4: setting up the scales. The scale for each axis is different. On the horizontal axis its going up by 1. On the vertical axis its going up by 20)

Time Pulse rate(beats per minute)

0 70

1 78

2 97

3 108

4 102

5 87

Step 5: draw the line

Step 6: add a title

Step 1: Draw the axes

Step 2: Pulse rate depends on the time so it goes on the horizontal axis.. Time goes on the vertical axis.

Time (Minutes)

Puls

e ra

te (b

eats

per

min

utes

)

Step 3: Label them

Step 4: Setting up the scales. Count how may squares represent one. (same interval).

The scale for each axis is different. On the horizontal axis its going up by 1. On the vertical axis its going up by 20)

Step 5: Putting up the values and draw the line

Step 6: Add a title0 1 2 3

20

40

60

Graph of pulse rate after exerciseTitle

Scale

Evaluation

and

Feedback from each student