How to Create Bar and Line Graphs

Draw the Axes

Identify the Axes Y- Axis X- Axis

Identify the Axes Y- Axis X- Axis Dependent Variable (what is observed and measured) X- Axis Independent Variable (what is changed by the scientist)

DRY MIX One way to remember which data goes on which axis is the acronym DRY MIX. D.R.Y. M.I.X. D- Dependent M-Manipulated R- Responding I- Independent Y- Y-axis X- X-axis

Write an appropriate title for the graph at the top. The title should contain both the independent and dependent variables. Example: How Temperature Affects The Respiration Rate of Goldfish

Scale The min and max numbers used on each axis. (Does not have to begin at zero). The min and max numbers used should be a little lower than the lowest value and a little higher than the highest value. Chose a scale that will take up most of the graph paper This allows you to have a smaller range which emphasizes the comparisons/trends in the data.

The Best Scale Graph #1 The Y-axis scale is from 0-100 but the largest value is only 35. Graph #2 The Y-axis scale is now from 0-40. ---2nd Graph does a better job emphasizing the comparisons between coins.

Steps to Find Scale Find the range of the data for the Y Axis (67-32= 35) Count number of lines/boxes on axes (20) Divide the range number by the number of boxes (35÷20=1.75) round to 2 to make easier Each box will be worth 2 degrees Repeat for the X Axis (6÷20=0.33) Each box is worth less than a day, 3 box =1 day Each third line should be labeled with the day

Intervals The interval is the amount between one value and the next Look at your minimum and maximum values you set up for both the Y and X-axis. Use appropriate interval for the scale you have chosen. Highly recommended to use a common number for an interval such as 2, 5, 10, 25, 100, etc.

Intervals The interval for the Y-axis is 8 The X-axis does not have numerical data and does not need an interval.

Labels Both axes need labels so we know exactly what the independent and dependent variables are. The dependent variable must be specific and include the units used to measure the data (such as “number of drops”). DV label IV label

Labels DV label IV label

TAILS T.A.I.L.S. Scale Title Axis Another handy acronym to help you remember everything you need to create your graphs….. T.A.I.L.S. Title Axis Interval Labels Scale

T.A.I.L.S. Title: Includes both variables Axis: IV on X-axis and DV on Y-axis Interval: The interval (4) is appropriate for this scale. Label: Both axes are labeled. Scale: Min and max values are appropriate.

Bar Graphs vs Line Graphs

Bar Graphs Bar graphs are descriptive. They compare groups of data such as amounts and categories. They help us make generalizations and see differences in the data.

Line Graphs Line graphs show a relationship between the two variables. They show how/if the IV affects the DV. Many times, the IV plotted on the X-axis is time. They are useful for showing trends in data and for making predictions. Can be used to compare multiple sets of data, using different lines within the same graph

Example

Multiple Sets of Data When graphing multiple data sets on the graph, use a distinctive color of pen, or style of line, for each data set. Place an example of the color or line style off to the side of the graph (Key) Label it with the name of the information being displayed. For example: Seedlings