Myrtle the Fun Loving Doll is 24 inches tall. When she gets mad she
grows 3 inches per hour. She's been
straight mad a long time. How many hours
will it take for her to be 45 inches tall?

The major difference is that a histogram is only used to plot the frequency of score occurrences in a continuous data set that has been divided into classes, called bins.  bar charts, on the other hand, can be used for a great deal of other types ofvariables  including  ordinal  andnominal  data sets.