1. Graphing Guide

2. What are you graphing? Systematic Observation or Experiment
Not every investigation is an experiment, some are systematic observations
Experiment
Manipulating a variable to compare differences
Which amount of Mentos will produce the highest stream when dropped in Diet Coke?
Independent
Dependent
Systematic Observation
Answering a question with a plan
What happens when three Mentos are dropped in Diet Coke?
Data is often qualitative, but can also be quantitative

3. Data Chart Great tool for data collection Drawbacks: Can be very large
Year
Enrollment (in mill)
2000
41.2
2001 42
2002
42.8
2003
43.5
2004
44.1
2005
44.8
2006
45.6
2007
46.1
2008
46.5
2009
46.9
2010
47.2
2011
47.7
2012
48.6
Great tool for data collection
Drawbacks:
Can be very large
Difficult to see trends or relationships
Cannot easily make predictions

4. Chart or Graph? Year Enrollment (in mill) 2000 41.2 2001 42 2002 42.8
2003
43.5
2004
44.1
2005
44.8
2006
45.6
2007
46.1
2008
46.5
2009
46.9
2010
47.2
2011
47.7
2012
48.6

5. Formulating a Graph Graphs compare two variables
Independent variable: The variable the scientist manipulates; the “cause”
e.g.: type of soda, type of mentos, number of mentos
Put on X-axis
Dependent variable: The variable that is measured; the outcome or data; the “effect”
AKA outcome variable
e.g.: Height of soda stream
Put on Y-axis

6. Title: “Y as compared to X”
What’s missing?
Line of best fit
-Ease of prediction
-Derive equation
Should display appropriate range
Title: “Y as compared to X”
Label Axis
Include units
Gridlines not always necessary
Label Axis
Include units

7. Types of Graphs A B C
School district budget allotted to different departments
Gas sales from each gas type
Proportion of plant varieties at nursery
Public school enrollment in the past 10 years
Average price of gas from 2004-present
Plant growth over a week
Number of public universities in different US states
Current gas prices at BP, Exxon, Shell, and Racetrac
Final plant growth of plant grown in light and in dark
Pie Chart
Line Graph
Bar Graph
Compares divisions of a whole
Reports percentages
Compares variables over time
Or over a spectrum of some sort
Compares data that are in distinct groups or categories

9. Your Task
Create graph of your group’s data
Create graph of class data