1. How and Why are Graphs Used in Science?

2. Why do Scientist’s Use Graphs?
Interpolating Data
Displays data in a easy to read format.
Relationships easy to recognize
Can be used to predict future events
Interpolating Data – finding the value in between 2 values on a drawn graph
Extrapolating Data- finding the value of a future event base on a previous pattern and trends.

3. Variables
Independent Variable – Variable that controls the other variable
*****Time will always be an independent variable b/c we cannot control time.
*** Independent Variable will always be plotted on the X-axis
Dependent Variable – Variable that is determined by the independent variable

4. Which is the independent and dependent variable?
Example: Temperature of Planet and distance from the sun
****THINK
Does the temperature control the distance from the sun?
Does the distance from the sun control the planet’s temperature?
INDEPENDENT VARIABLE IS?? Distance from the sun
DEPENDENT VARIABLE IS?? Temperature of the planet.

5. How Do We Create a appropriate Scale For a Graph?
Determine the maximum value that will be plotted and round it up to the nearest number
Count the total number of boxes on the axis
Maximum Value_______
Number of boxes on axis

7. Rules for making Graphs
Use an appropriate scale (GRAPH SHOULD FIT THE PAPER)
Label axes with quantity and units
Example: Quantity measure = Distance Units = Meters
Distance (Meters)
Quantity = Temperature Units = Degrees Celsius
Temperature (Degrees Celsius)
Independent Variable on the X axis!
Dependent on the Y axis

8. Graphing Relationships
Helps to visualize cause and effects of data
Predict future changes based on trend or patterns.

9. Direct Relationships Both variables increase
Ex: As the distance from the sun increases the time it takes a planet to revolve around the sun increases.

10. Inverse or Indirect Relationships
As one Value increases the other decreases
Ex: As the price of Tickets increase less ppl attend events.

11. Cyclic Relationships Repeating event Predictable
Examples of cyclic events:
Ocean Tides
Sunrise and Sunset
Moon phases
Seasonal Temps
Sun spots
Nonpredictable events:
Earthquakes, volcanic eruptions

12. Dynamic Equilibrium One variable is staying the same
Ex: Ecosystems stay relatively constant unless a dramatic event occurs

13. Dynamic Equilibrium

14. Let’s Review