How to make a line graph Line graphs are powerful in science because of the relationship they show between two variables (showing how one variable changes as the other changes).

Step One You need the topic of what you are showing at the top of the graph---remember, ANYONE should be able to see and understand your data ---no matter who picks up your paperwork. If you have done it correctly, anyone should be able to read what you have written and say, “Oh, I see, you are showing me the results of the lab on bubble sizes of different brands of bubble gum”; or, whatever else your lab was about.

Remember---you need the topic at the top of your graph: Notice that the topic is at the top.

Step Two (2): You need a “legend” which tells you what the variables are represented by. The legend can be put under your graph or to the sides—be sure it is not too crowded so it can be easily understood. On the line graph below, the legend is the small box which lists the “Products” and the colors they are represented by on the graph.

The legend can be done in many ways: Notice the graph on the left has different colors and also a different shape is used with the colors. If you had not noticed so does the first line graph we showed which is on your right:

Why can’t we use a bar graph—we already know those? You can, however, it is good to know how to do more than one type of graph. Sometimes it is actually easier when you are graphing 10 numbers to do the line graph. Line graph -vs- Bar graph

3rd step: You must decide your number range for graphing and also the items that are being listed. Do you automatically just start with “0” and make numbers up to “100?” NO!! That may be a waste of your time and paper space. You look at the number ranges you are looking at and then decide. Yes—you would begin with a “0” but decide how high to go and how to space your increments of numbers—example—0, 2, 4, 6, etc. or 0, 5, 10, 15, etc. or 0, 3, 6, 9, etc. Sometimes you may need to simply go with 0, 1, 2, 3, etc. until you reach your highest needed number,

Notice the different range of numbers on the following line graphs:

Also, you will want to consider your graph paper lines to plan accordingly so all information will fit.

4th:Be sure to draw a margin line so you will have a space to write the topics, numbers, items, etc.

5th step: Now that you have decided the topics, numbers, and space required.. . You begin to make your graph. Still confused? Line graphs can be used to show how something changes over time. Line graphs are good for plotting data that has peaks (ups) and valleys (downs), or that was collected in a short time period. The following pages describe the different parts of a line graph.

Next: Your graph title: The Title The title offers a short explanation of what is in your graph. This helps the reader identify what they are about to look at. It can be creative or simple as long as it tells what is in the graph. The Title The title offers a short explanation of what is in your graph. This helps the reader identify what they are about to look at. It can be creative or simple as long as it tells what is in the graph.

The Legend—very helpful information: The legend tells what each line represents. Just like on a map, the legend helps the reader understand what they are looking at.

The source can be added at the bottom of your graph. In our case, the source is our classroom with the class period and school year. The Source The source explains where you found the information that is in your graph. It is important to give credit to where the information came from.

Y-Axis In line graphs, the y-axis runs vertically (up and down). Typically, the y-axis has numbers for the amount of stuff being measured. The y-axis usually starts counting at 0 and can be divided into as many equal parts as you want to. In our bubble gum graph, our y-axis will be number range from 0 to the largest size bubble blown in centimeters (cm).

The Data The most important part of your graph is the information, or data, it contains. Line graphs can present more than one group of data at a time. In your graph, the data shows the average size bubbles blown for each type of the gums used. We will also design and make a bar graph. This one will show the largest bubbles blown from each class period.

X- Axis X-Axis In line graphs, the x-axis runs horizontally (flat). Typically, the x-axis has numbers representing different time periods or names of things being compared. In your graph, the different trials of the bubble blown will be used.

OKIE- DOKIE!!! Now you know all you need to in order to complete your bubble gum graphs. Let’s get at it—They are due when you return to class along with your lab write-up and the lab data sheets.

Now---you should be an expert!! Be like this: Don’t be like this guy: