Bar Graph vs. Histogram Graph

Good day friends! Today's Blog is all about graphs. A graph is a "picture that displays data and [is] used to tell a story." Bar graphs and circle graphs are the most common graphs elementary aged students will see in school. First I'm going to compare and contrast bar graphs and histogram graphs because at first glance they appear identical.

Bar graphs are "used to represent situations where the data are categories." I discussed categorical data in my past blog (please refer to it if you have questions). You can arrange bar graphs "randomly, alphabetically, or by popularity." Don't be confused, bar graphs (or categorical data) is not absent of numbers but the categories or choices aren't numerical. If you had your first grade class choose their favorite holiday and 12 people chose Christmas and 3 chose Halloween then you can see that numbers are attached to the categories.

Histogram graphs "can be used to summarize numerical data that are on an interval scale, either discrete or continuous." Histograms are good graphs to use for ranges of data, data that's best read if in order. A histogram must be in order

You can begin to introduce graphs to children as young as first grade but the depth to their understanding may take a few years to develop. For instance, first graders can be taught to make simple bar graphs or line plots and they can analyze data from the two types of graphs. However a histogram has a little more depth to it and the vocabulary one might use to explain a histogram would probably be over the heads of most first graders. I would suggest introducing histograms in second or third grade.

*A wonderful book to use to begin teaching about graphs to young children is Lemonade for Sale by Stuart J. Murphy and Illustrated by Tricia Tusa.*

Carpe diem,

Cass

* Links to other helpful websites about bar graphs &   histograms:
1) Creating Bar Graphs - http://www.readingrockets.org/article/43814/
2) Histograms - http://www.mathsisfun.com/data/histograms.html
3) Bar Graphs -
http://www.mathsisfun.com/data/bar-graphs.html