I started off the lesson by showing children a red 3-cube train and a blue 5-cube train, with the cube trains aligned at one end.
To check their answers, I have children count the number of cubes in each cube train. I repeat this several times, comparing two cube trains of different lengths.
I then explain to children that in today’s lesson they will read graphs by comparing lengths of colored bars.
In the standard MD.C.4, students will need to not only read the bar graph, they will also have to be able to answer questions about which data point has more or less, and compare them to each other. A bar graph uses shaded bars to represent data, and children need to look at the length of the bar to determine the number. In order to analyze and interpret data on a bar graph, I have found that it is important for children to be able to correctly label the parts of a graph.
By ensuring that their bar graphs will have the correct title and labels, students will also be meeting Mathematical Practice 6, attending to precision. This practice is important in that students will be labeling their graph and axis to clarify the quantities in their graph.
I read the following problem aloud to the class. (The picture graph is located in the PowerPoint Read a Bar Graph.ppt found in the resources section.)
Emma’s class made this picture graph. What question could Emma’s class answer using the graph?
I then have students write down a question about the bar graph. After writing their questions, I have children exchange papers with a classmate. I have the classmate answer the question, and then have the child checks the answer.
Looking at the bar graph on the second slide, I guide children through the model with the following questions.
In this standard, MD.C.4, some students may have difficulty finding the value for a given bar in a bar graph. To help with this, I like to teach my students to touch the end of the bar and follow the line to determine the number that the bar is representing. This helps them make the connection that the end of the bar represents the data point.
To close out the lesson, I have students draw a bar graph in their math journal, using the following information:
Graph title: How to Tie Shoes
7 students know how to tie their shoes
3 students do not know how to tie their shoes