MHS Chemistry
How to Make a Good Graph

Remember that the x-axis goes across and the y-axis goes up and down.

  1. Every graph should have a title ("Mass and Age of Pennies").
  2. Every graph should have an MLA heading (include your partner's name, class, date).
  3. Some graphs may need a key (to explain colors or symbols).
  4. The graph should fill the available space. If you make a graph with a computer, you can copy & paste it into your final report, and size it to fit your layout.
  5. If you make a graph by hand it should always be on graph paper.
  6. The axes should each be titled AND labeled to match the data table ("mass of pennies, grams").
  7. The range of each axis may be different. They should each be large enough to cover the needed range without lots of extra space. They do not need to start at zero.
  8. The scale of each axis may be different, but each one must be consistent. If one box represents one year at the beginning of the graph, one box always represents one year.
  9. The axes should be numbered to the same number of decimal places as the data was recorded. You don't need to number every box - usually every five or ten boxes will be adequate.
  10. The independant variable always goes on the x-axis. If time is one of the measurements being graphed, it always goes on the x-axis.
  11. Error bars may be used to indicate uncertainty in a measurement. The proper use depends on the graph and will be discussed as necessary.
  12. Sometimes a line connecting points is OK. When this is true, it is often best to draw the best smooth curve that goes near the data points. Look for general patterns rather than details.
  13. If any calculations are done using points from a graph, the points used should be indicated (a small arrow labeled "calculation 1" should be adequate).
  14. The less ink you use, the easier it is to read. Try it!
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