Picture Graphs and Bar Graphs

Graphs are fun and colorful ways to organize and show data (information). In second grade, you will learn how to read, understand, and create two very important types of graphs: picture graphs and bar graphs.

What is a Picture Graph?

A picture graph uses pictures or symbols to show how many items are in each category.

The most important part of a picture graph is the key. The key tells you exactly what each picture stands for.

Sometimes, one picture equals one vote. But sometimes, one picture can stand for more than one!

Example: Imagine a picture graph showing favorite foods. The key says: 😊 $= 2$ votes

If the "Pizza" row has $4$ smiley faces, how many votes did pizza get? You count by twos: $2, 4, 6, 8$. So, Pizza got $8$ votes!

What is a Bar Graph?

A bar graph uses rectangular bars to show data. The bars can go up and down (vertical) or side to side (horizontal).

To read a bar graph:

1. Look at the labels to see what categories are being compared (like colors, sports, or pets).
2. Look at the numbers along the side or bottom.
3. Follow the top of the bar to the number line to see how many items are in that category.

Answering Questions Using Graphs

Once you know how to read a graph, you can act like a detective and answer questions about the data!

• Finding the Total: If a question asks "How many students voted in all?", you need to find the number for every category and add them together. $\text{Total} = \text{Category 1} + \text{Category 2} + \text{Category 3}$
• Comparing Categories: If a question asks "How many more students prefer soccer than basketball?", you need to subtract. Find the number for soccer, find the number for basketball, and subtract the smaller number from the bigger number. $\text{Soccer Votes} - \text{Basketball Votes} = \text{Difference}$

Creating Your Own Graph

You can easily make your own bar graph or picture graph using a tally chart.

1. Count the tallies: Look at your tally chart and count the marks for each category. (Remember, a group of tallies with a diagonal slash across it equals $5$).
2. Set up your graph: Write your categories on one side and your numbers on the other.
3. Draw the data:
   • For a bar graph, draw a bar that reaches exactly up to the correct number.
   • For a picture graph, draw the correct number of pictures (and don't forget to write down your key!).