Understanding Science Graphs

The Scientific Method and Graphs

• Scientific experiments involve:
  • Making observations
  • Formulating a hypothesis
  • Designing and conducting an experiment
  • Collecting and evaluating data
  • Accepting or rejecting the hypothesis
  • Formulating a new hypothesis if necessary
• Independent variable (x): the cause, what is being manipulated in order to test a hypothesis
• Dependent variable (y): the effect, what is being influenced by the independent variable
• Types of data:
  • Numerical data: numbers
  • Categorical data: non-numerical values (e.g., country names)

Line Graphs and Tables

• Line graphs and tables are used to record and compare independent and dependent variables
• Tables list x and y values next to each other separately
• Line graphs chart x and y values as data points (x, y) on a graph
• Line graphs are used to compare numerical data and show trends
• A line graph has two axes:
  • The x-axis (horizontal) plots independent x values
  • The y-axis (vertical) plots dependent y values

Interpreting Graphs and Charts

• Different types of data require different graphs and charts
• The way information is understood from these charts and graphs varies
• Types of graphs and charts include:
  • Line graphs
  • Bar charts
  • Pie charts
  • Flow charts

Line Graphs

• A line graph plots independent (x) and dependent (y) variables on a graph to create a visual trend
• The graph contains an x-axis and a y-axis
• Variables are represented as "coordinate pairs" (x, y)
• Line graphs are used when comparing strictly numerical data and are helpful when comparing small changes in a trend over time

Bar Charts

• A bar chart does not use coordinate pairs
• Rectangular bars are used to represent different values
• The height of the bar is proportional to the value of the data represented
• Bar charts may plot data vertically or horizontally
• Bar charts are useful in comparing larger changes or differences in data among different groups
• Bar charts can be used with non-numerical data

Pie Charts

• Pie charts are useful when comparing percentages
• Each "slice" of the pie is a percentage of a whole population or data set
• The different slices are the independent variables (x) and the size of the slice is the dependent variable (y)

Flow Charts

• Flow charts are helpful when comparing non-numerical concepts
• Flow charts show cause and effect relationships
• Flow charts simplify complex relationships or procedures by showing the steps in a process in sequential order
• Although they provide no numerical data, flow charts are often used in science to show cause and effect relationships

Learn to interpret scientific experiments and data. This quiz covers the basics of understanding science graphs, a useful skill for anyone.