1. Graphs for Integrated Science
Why use a graph?
What kinds of graphs are there?
How does one make a graph?

2. Why use a graph? Graphs communicate information visually
Graphs tell a story –
Show patterns and trends
Not language dependent
Used in newspapers, magazines and businesses around the world

3. What kinds of graphs are there?
Three types used in integrated science
Bar graphs: a graph drawn using rectangular bars to show size of a value
Line graphs: a graph that uses points connected by lines to show how something changes in values
Pie Charts: percentage data is shown a circle divided like pie pieces.

4. Bar Graphs Bar graphs help compare categories
Usually independent variable (factor that differs from group to group) make up categories
Categories placed upon horizontal axis
Categories often qualitative or discrete values

5. Line Graphs Line graphs help show relationships and predictable laws
Data is quantitative
Values are continuous
Dependent variable is on y axis
Key or legend necessary if more than one line

6. Pie Charts Show percentage data Data is quantitative
Usually has key/legend to identify categories
Doesn’t use distinguish type of variable

7. Parts of a graph Title: Appears at the top and describes the graph
Axes with labels: Reference line drawn on a graph to show values; usually one vertically (y) and on horizontal (x); define the data graphed; (axis is singular)
Scale: uniform tic marks (or categories) that show the value of each interval or square; every square must equal the same amount.
Legend/Key: chart to help identify different trials or parts of experiment

8. Parts of a graph Descriptive TITLE
SCALE: tic marks (or categories) are uniformly incremented
Note: this graph does not start at 0,0 but starts at (1,0) as the first data is day 1, temp 43.
AXES Labels
Independent variable x-axes
Dependent variable y-axes

9. What kind of graph should I use? Line or bar?
Look at the table of your results:
If this column (Independent data) has
Only certain fixed values, or qualitative categories, use a bar-graph:
A continuous range of values, use a line-graph:

10. How do I make a line graph?
1. Draw in the axes and use simple scales.
Put the dependent variable on the vertical y-axis
Put the independent variable on the horizontal x-axis

11. How do I make a line graph?
Draw in the axes and choose simple scales.
To find a scale,
Find the range (highest value – lowest value)
Divide the range by the number of squares
Choose the closest simple values:
1 large square = 1 centimeter (1 cm) or
1 large square = 2 cm, or 5 cm, or 10 cm
Never choose an awkward scale, like 1 square = 3 cm or 7 cm
Make tic marks and label the axes

12. How do I make a line graph?
Plot the points neatly.
To mark the point, use an X x
Usually you need 5 or more points for the graph. x x x x x
Re-check each one before your next step.

13. How do I make a line graph?
Draw the “best fit line”
If the points form a straight line… …draw the best straight line through them
If the points form a curve,
…draw a free-hand curve of best fit

14. How do I make a line graph?
Check Outliers
If a point is not on the line,
then it is “an outlier.”
Check your equipment & data
Title the graph using descriptive words
Use words that tell the reader what the graph is about. For example, “World population growth since 1900.” Often you will use the dependent and independent variables in the title.
Title the graph using descriptive words
Use words that tell the reader what the graph is about. For example, “World population growth since 1900.” Often you will use the dependent and independent variables in the title

15. How do I make a line graph?
In summary:
Draw in the axes and choose good scales,
with the dependent variable on the y-axis
Plot the points carefully using an X.
Draw a line of best fit
using a ruler for a straight line graph,
or draw free-hand for a curved graph
Check outliers.
Add a descriptive title to the graph

16. Webography
Free Support for Physics for You. Web. 27 Sept Graphing Scientific Data. Web. 27 Sept Google docs. "Displaying Data in Tables and Graphs." Algebra to Go: a Mathematics Handbook. Wilmington, MA: Great Source Education Group, Print.