Elements of a Graph

Insanity of Statements

Why use a graph?Graphs are very useful tools in science:

A graph is used by scientist to organize the facts so they can be analyzed and conclusions can be drawn.

Graphs are pictorial representation of recorded information.

Used to show the relationship between 2 or more different factors.

Graphs make trends in data easy to see.Graphs allow us to predict data that is not measured.

There are several different types of graphs:BAR GRAPH

CIRCLE/PIE GRAPH

LINE GRAPH

Bar GraphUsed to compare data for several

individual items or events.Number of pets in Mrs. O’Neill’s block 3 class.

Circle or Pie Graph:Used to display data that are parts

of a whole.Can be compared by percentages or by the size of the “sections/parts”.

The different types of pies that the students in Mrs. O’Neill’s block 3 class enjoy eating.

Line GraphsUsed to show something that is being measured as it changes over a period of time.

Can be used to predict what will most likely happen next.

Line graphs allow us to predict data that is not measured:

Extrapolate: extend graph along the same

slope, above or below the measured data.

Interpolate: predicting data between two

measured points on a graph.

Rules for making a line graph:

#1 Assign and label your X and Y axes:X axis:

Located on the bottom of the graph /horizontal axis

Shows the most consistent or independent variable

The independent variable occurs no matter if the experiment is occurring or not. It is most often time.

Independent variable is controlled by the person conducting the experiment.

X

Y

Y axis:Located on the side of the graph /vertical axis

Shows the variable which is dependent on the other variable.

The dependent variable is the one that depends on what happens in the experiment

X

Y

Example:

Independent variable:

- time in years

Dependent variable:

-population size

#2 Make a scale for each axes based upon the data collected.

#3 Utilize as much of the graph paper as possible.

#4 Plot the data points.

#5 Connect the data points with a straight

edge.

#6 Give the graph a meaningful title.

#7 Provide a key if graphing more than one

set of data points on the same graph.

Graphing PracticeHow far does a soap box car travel after 10

seconds?Time (seconds)

Distance (meters)

0 0

1 2

2 8

3 18

4 32

5 50

6 72

7 98

8 128

9 162

10 200

Q & AWhat is the rate of photosynthesis at 10C?

50

What is the dependent variable in the graph? Rate of photosynthesis

At what temperature is the rate of photosynthesis at its highest?

30 degrees