Graphing+rules+in+science

= ** Rules for Graphing in Science ** =

A graph shows how two things are related to each other. The two things in a graph that change are called the variables. A graph will help you understand the data you have gathered in doing your activity.

__Follow these steps whenever you make a graph:__ kind of graph is called a **complex graph**; it needs a key telling what each color stands for. In these graphs, use colored pencils, no markers.
 * 1) In Science class we will always **use line graphs**, never bar or pie graphs.
 * 2) Use **only pencil** to make a graph, never pen.
 * 3) Mrs. O. will let you know if you are to use your graph paper **horizontally or vertically** for the graph you are to make. Always use the graph paper provided, unless told otherwise.
 * 4) Decide which variable goes on the horizontal axis (x-axis) and which goes on the vertical axis (y-axis). **What is the independent variable (x-axis) and what is the dependent variable (y-axis)?**
 * 5) Put the **name of each variable under (or to the side of) its axis**. Make sure you **include the metric unit** in which it was measured. Write these units in parentheses next to the name of each axis. Make the axes darker in color, leaving enough space to write the numbers and the names.
 * 6) Choose scales that will stretch the horizontal scale (x-axis) and the vertical axis (y-axis) **AT LEAST 3/4 of the way across (or up) the page**. Your scales for each axis may be different. However, for whichever scale you use, the **numbers on the axis must be spread out evenly** with the same amount of spaces between each number. These numbers must allow for the **maximum data point to be at the top or the end of the axis. Usually we have “0” at the beginning, but not always.**  It is not necessary to label every line on the graph. Make sure the scale you use is easy to read. Write numbers directly under (or to the side of) each line, not the boxes.
 * 7) Locate each point on the **graph**. Check over the placement of each point to make sure you have done it correctly. Make your dots for the graph large enough to be seen through the line.
 * 8) If possible, **draw a smooth line** (whether a straight line or a curve) through all the points. This is called the “best fit line.” If you think all the points belong on a straight line, use a ruler to draw the line. If you think the points belong on a curve, draw the curve very lightly at first, then darken it when you are sure of it. Both of these lines will probably not go exactly through all of the points because of errors in measurement. Do not try to force the line to go through all of the points perfectly. Make the line an average line through all the points. There should be an equal number of points above the best fit line as there are below it.
 * 9) Give your graph a **reasonable title** using the names of the axes.
 * 10) Use different colored pencils for different things being graphed on the same axes. This


 * Remember:** To receive full credit for your graph, you need to tape the graph into your notebook in the Activity Report properly (right side up) on a separate page from the procedure’s page.