Session 2 Graphs

DIFFERENT TYPES OF GRAPHS Line graphs Sector graphs Picture graphs Bar graphs Step graphs Column graphs

The main types of graphs used in science are: Type of graph Form of information Why they are used Column/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.

Line graphs

The ‘vertical-axis’ and the ‘horizonatl-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.

Line graph Summary A line graph has two lines or axes. Is often used to represent a set of data values in which a quantity varies with time One is the horizontal axis which goes from side to side. Line graph The other is the vertical axis which goes up and down. A line graph is used to show the relationship between two variables. Shows how one thing is affected by another.

Plot the points accurately with a small dot or x. Things you should follow when drawing a line graph use graph paper Plot the points accurately with a small dot or x. use a pencil draw in the two axes with a ruler

Line graph Line graphs are useful for showing how things change over time. Mass depends on the temperature Vertical axis Horizontal axis Jump= 50 Spaces= 2 Each line =50/2= 25 Temperature does not depend on mass Jump= 20 Spaces= 2 Each line =20/2= 10

Pulse rate(beats per minute) Example 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) 70 1 78 2 97 3 108 4 102 5 87

Pulse rate (beats per minute) 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) Step 5: draw the line Graph of pulse rate after exercise Step 6: add a title Time Pulse rate (beats per minute) 70 1 78 2 97 3 108 4 102 5 87 Pulse rate (beats per minutes) Time (Minutes)

Title Graph of pulse rate after exercise 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. Step 3: Label them Step 4: Setting up the scales. Count how may squares represent one. (same interval). Pulse rate (beats per minutes) 60 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) 40 20 Step 5: Putting up the values and draw the line 1 2 3 Scale Time (Minutes) Step 6: Add a title

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By Zani Alam