1. Graphing in Science
A picture is worth a
thousand words.

2. There are three main types of graphs:
Pie
Bar
What are these graphs trying to communicate?
You see numbers and names, but without background we really do not know what these graphs are trying to communicate.
Line

3. When to Use A Line Graph:
Use when trying to interpret information beyond the known data
Interpolation: predicting the data BETWEEN the known points on the graph
- Extrapolation: predicting data BEYOND the known points on the graph
Temp °C
Time in Seconds

4. When to Use A Bar Graph:
Use to show how something changes over time or to compare items.
Used especially when collecting data over many weeks or from year to year.
# of State Championships
High Schools

5. When to Use A Pie Graph: Use to show percentages of a whole or group.
They do NOT represent changes over a period of time.
% of Students in SBISD
The total of the pie should add up to 100%.
Anglo – 58%
African – 23%
Hispanic – 10%
Asian – 9%
* Data is pretend.

6. Let’s look at some examples of how graphs are used...

7. When a scientist conducts an experiment, he/she carefully observes what is happening.
He/She records information called data.
Time (s)
Temp. (C)
0 s
15 0
30 s
18 0
60 s
20 0
90 s
22 0
The data is often a set of numbers.

8. #'s It is important for scientists to be able to take data...
Such as numbers
And make it into a visual “picture” of what the data says...
In order to make valid conclusions from experiments...

9. What does this data look like?

10. Data is a ……….
picture for your brain!

11. You need to know how to recognize the
To make graphs
You need to know how to recognize the
independent
variables
dependent

12. Experiment #1: You are measuring the temperature in degrees Co of a water sample as it is heated over a period of 30 minutes.
You DECIDE the interval (each minute) to collect the data (temperature).
Time (min)
Temp. (C)
Interval at which you collect your data or independent variable
The data being collected or dependent variable at
0 min
0 0
it is
1 min
0 0
2 min
0 0
3 min
1 0
4 min
5 0

13. A variable is what “changes” in an experiment.
Variables
Experiment: You are measuring the temperature in degrees Co of a water sample as it is heated over a period of 30 minutes.
changes
changes
A variable is what “changes” in an experiment.

14. In this table there are two variables:
time
temperature

15. Which is the independent variable?
time
...is the independent variable because this is the interval you chose to collect data. The scientist “controls” this variable.
temperature

16. Which is the dependent variable?
time
temperature
...is dependent on the time so the temperature is the dependent variable. This is the data that a scientist collects.

17. Constructing a Line Graph
Determine the independent and dependent
variables in your table.
2. Label each axis: x-axis independent and y-axis
dependent.
3. Find the variable range: “middle value” is halfway on
the graph scale.
4. Number and label the each axis.
5. Plot the data points.
6. Connect the data points.
7. Title the graph.

18. 1. Determine the independent and dependent variables in your table.
You chose at what “interval” to collect the data.
This is information (data) you collected at that interval.
time
temperature
This is the INDEPENDENT
Variable.
This is the
DEPENDENT
variable.

19. 2. Label each axis: x-axis independent and y-axis dependent.
Temperature
Dependent
Variable y x
Time
Independent Variable

20. 7 or 8 needs to be about here... 4. Number and label the each axis.
3. Find the variable range: “middle value” is halfway on the graph scale.
low
100 90 80 70
Middle 60
Temp. in C 50 40 30 20 10
7 or 8 needs to be about here... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Time in Minutes
high
4. Number and label the each axis.

21. Temperature of “Liquid A” as It Is Heated
5. Plot the data points.
Temperature of “Liquid A” as It Is Heated
0, 0
1, 0
100
2, 0 90
3, 3 80
4, 14 70
5, 25 60
6, 36
Temp. in C
7, 47 50
8, 58 40
9, 69 30
10, 80 20
11, 91 10
12, 98
13, 98 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
14, 98
Time in Minutes
15, 100
6. Connect the data points.
7. Title the graph.

22. Line graphs take data and give us a picture of what that data looks like:
Temperature
Time
This graph helps us to understand the relationship between time and temperature.

23. Constructing a Bar Graph
Similar to a line graph in determining the
independent and dependent variable.
Label each axis: x-axis independent (what is being compared)and y-axis dependent (usually the # or value).
3. Determine the name and color/pattern for each bar.
4. Make a legend or a key for the information.
5. Plot the information.
6. Title the graph.

24. Experiment #2: You are trying to compare the quantity and colors of M&M’s in two different packages.
Similar to a line graph in determining the independent and dependent variable.
Color
Pkg 1
Pkg 2
Red 7 5
Blue 6 8
Orange 10
Green 12 14
Yellow 9
Brown 4 2

25. Label each axis: x-axis independent (what is
being compared) and y-axis dependent
(usually the # or value).
# of M&M’s
Colors of M&M’s

26. 3. Determine the name and color/pattern for each bar.
4. Make a legend or a key for the information.
5. Plot the information.
# of M&M’s
Colors of M&M’s

27. Comparison of Colors of M&M’s In 2 Packages
6. Title the graph.
Comparison of Colors of M&M’s In 2 Packages
# of M&M’s
Colors of M&M’s

28. Constructing a Pie Graph
1. Collect the known data from your resources.
2. Determine the value for each slice of the pie.
3. Name each slice and select a color/pattern for each piece to be represented on the graph.
4. Make the legend / key for the graph.
5. Total the graph – Should add up to 100%.
6. Title the graph.

29. Experiment #3: You are trying to
Compare the relationship among the different high schools in Spring Branch ISD.
1. Collect the known data.
Grade Level
# of Students
MHS
2201
NHS
1740
SSH
1915
SWHS
1947

30. 2. Determine the value for each slice of the pie.
HS’s
# of Students
MHS
2201
NHS
1740
SSH
1915
SWHS
1947
TOTAL
7803
Add up the TOTAL number of all students then divide by that group to get the percentage of students.
MHS % = 2201 students
7803 total students
MHS % = 0.282
Move decimal point 2 places to the Right = 28%
Repeat above steps with the remaining data.
HS’s
Percentage
MHS
28%
NHS
22%
SSH
25%
SWHS
TOTAL
100%

31. 3. Make the legend / key for the graph.
Name each slice and select a color/pattern for each piece to be represented on the graph.
SWHS
MHS
SSH
NHS
3. Make the legend / key for the graph.
MHS – 28%
NHS – 22%
SSH – 25%
SWHS – 25%

32. % of Students at High Schools
4. Total the graph – Should add up to 100%.
MHS – 28%
NHS – 22%
100%
SSH – 25%
SWHS – 25%
% of Students at High Schools
in SBISD
5. Title the graph.
MHS – 28%
NHS – 22%
SSH – 25%
SWHS – 25%