Graphing Rules
Grade 8– Physical Science
Mrs. Petit
(Put this sheet in the Reference Section of your binder)
As you complete graphs in science class, there are some simple rules you should
follow.
1. Always use graph paper for your graphs. Use the “75% rule”. That is, if your graph
doesn’t cover nearly 3/4 of the graph paper, take a look at your axes again. In general, the
graph should be as large as possible, thus making the data points easily read. Do not,
however, extend your graph beyond the limits of the graph paper provided.
2. Choose your scale carefully. Let each space represent a convenient amount. The
range of numbers on each axis depends on the smallest and largest value for each variable. To
find the range, subtract the smallest value from the largest value for a variable.
3. Use a ruler to draw the x- and y-axes leaving a margin at each for labeling and
numbering. You should always label the x- and y- axes with the variable they are
representing and the unit of measurement.
“DRY MIX” can help you remember which variable belongs on the axis.
DRY represents Dependent – Responding - Y-axis.
MIX represents Manipulated – Independent - X-axis.
4. Always use pencil or colored pencils when creating your graphs.
5. Make sure you have a Title for the graph.
6. Create a key if needed.
GRAPHING PRACTICE
Grade 8 ~ Physical Science
II. Practice using the graphing rules above and create the following graphs.
GRAPH #1
a. Jamie bought a new video game and decided to keep track of his scores over a period of one week.
Day 1 – 150 pts
Day 3 – 200 pts
Day 5 – 265 pts
Day 2 – 375 pts
Day 4 – 420 pts
Day 6 – 485 pts
Create a bar graph of Jamie’s progress. Put the “Days” on the X axis and the “Points Scored” on the y axis.
1. What is the independent variable? _____________________________________________________
2. What is the dependent variable? ______________________________________________________
Using complete sentences state a conclusion about the data in graph # 1.
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
GRAPH # 2
Directions: Graph the following data tables using the appropriate type of graph. Be sure to: provide a title, a
label for the x & y axis, a key (if necessary), and an appropriate number scale.
1. The data table shows water temperatures at various depths in an ocean.
Water Depth (meters) Temperature (°C)
50
18
75
15
100
12
150
5
200
4
Using the information in the data table, construct a line graph on the grid, following the directions below:
-- Plot the data on the grid. Surround each point with a small circle and connect the points.
Example:
Problems Based on Graphing of Water Temperatures
1. Using complete sentences, state the general relationship between temperature and water depth. Example: As the water
depth increases/decreases, the temperature increases/decreases.
_________________________________________________________________________________________________
_________________________________________________________________________________________________
2. The approximate water temperature at a depth of 125 meters would be closest to: _____________
(a) 15°C (b) 8°C (c) 13°C (d) 3°C
GRAPH # 3
Display the data in a multiple line graph. How Much Beef and Chicken Do Americans Eat
Each Year? (Pounds per person)
Year
1989
1990
1991
1992
1993
1994
1995
* Source: U.S. Department of Agriculture
Beef
65
64
63
63
62
64
62
Chicken
41
42
44
46
49
50
52
1. What is the independent variable? _____________________________________________________
2. What is the dependent variable? ______________________________________________________
Using complete sentences state a conclusion about the data in graph # 3.
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________