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Analyzing your data:
Variables and Graphing
Organizing your data
In any investigation, organizing is the first step to
finding answers. Once you conduct an experiment,
you must organize your data.
Always create a data table before your experiment
starts, that way you can keep your data organized as
you work.
A data table has two columns to list the two variables
in your experiments.
Variables cont.
DEPENDENT VARIABLE = THE FACTOR THAT CHANGES
BASED ON THE INDEPENDENT VARIABLE-.
On a data table the dependent variable is on the right
side.
On a graph it is on the y-axis.
Examples:
Temperature: record the temperature as it changes
after set periods of time.
Mass- Mass of each object after something has
affected the object.
Temperat ure in Celsius
Student s who got sick 150 500
200 80
300 20
500 0
dependent
Controlled vs. Variable
Parameters
1. VARIABLE PARAMETER (independent
variable and dependent variables) – this is the
things you change in the experiment.
2. CONTROLLED PARAMETERS – these
are all the other factors in the experiment that
stay the same.
Examples: figure out which is
the independent and dependent
variable:
- A scientist checks how much his puppy grows each day for 20 days.
- A science student adds salt to 3 fish tanks at different rates to see how fast algae will grow in each tank.
- A student records how fast the cars go on the freeway at 5 different times during the day.
- A scientist takes the temperature of a beaker of cooling chemicals every 2 minutes.
Graphing
Data tables help you organize data, Graphs help you
understand and use the data.
Graphs make it easy to identify trends and make
predictions.
TREND = The relationship
between the independent
and dependent variable
(THE LINE)
Steps Cont.
3. Determine the Range and the Scale:
to find the RANGE subtract the smallest value of a
single variable from the largest value
For our Data: 500-150 = 350, so the x-axis must cover at
least 350 grams. 10-0 = 10 so the y-axis must cover
at least 10 cm.
The SCALE is the size that is used for each box on the
graph. There can be a separate scale for each axis.
The scale should be chosen such that the graph
spreads out to fill most of the available space. The
scale must go in equal increments
Amount of Protein (g)^ MuscleGrowth (cm)
150 5
200 10
300 3
500 0
Scale
Amount of Protein (g)^ MuscleGrowth (cm)
150 5
200 10
300 3
500 0
SCALE
SCALE
What it Looks Like
Population
Years
- Label the Graph
- Range and Scale
- Draw the Axes.
- Plot the Data Points
- Label the Axis
- Label the Axis
3 Main Types of Graphs
1. Line Graph 3. Pie Chart
2. Bar Graph
Make a scale for each data
table:
1. X- axis: 2. X-axis:
Y axis: Y-axis:
Amount of food (^) Hours of Sleep
Temperature in Celsius^ Students whofaint in formation
Don’t forget about variables…
INDEPENDENT VARIABLE = THE VARIABLE THE
SCIENTIST CHANGES.
Is always on the left side of the data table
Is always on the x-axis on the graph (horizontal)
DEPENDENT VARIABLE = THE VARIABLE THAT CHANGES
BECAUSE THE INDEPENDENT VARIABLE CHANGES
Is always on the right side of the data table
Is always on the y-axis of the graph (vertical)
Time Distance
Time
Distance
Independent
Dependent