Grade 2: Bar Graphs

Warm up with a quick recall on the board. Match each bar to the scale to read its value, then compare bars for most, least and difference. Keep bars equal width with gaps.

A bar graph shows counts for separate categories using bars of equal width, where the height (or length) of each bar stands for how many. Because the bars sit apart, a bar graph is for data in distinct groups, such as favourite fruits or pets, not for continuous change over time. Reading one means matching a bar to the scale on the axis. Model the method clearly, thinking aloud:

• Start from sorted, counted data (a tally chart), so students graph numbers they already found rather than inventing them.
• Build the axes together: categories along one axis, a number scale up the other, and agree what one square on the scale is worth before drawing.
• Draw bars of equal width with a gap between them, each bar as tall as its count, and label every bar.
• Read values back by tracing from the top of a bar across to the scale, especially when the count falls between two gridlines.
• Ask comparison questions: which category has the most, the least, and how many more one has than another.

Work this through step by step on the board, then have the class talk you through a second one.

• Tally: apple 4, banana 6, grape 3
• scale: each line = 1 fruit
• apple bar to 4
• banana bar to 6 (tallest, the most)
• grape bar to 3 (shortest, the least)
• banana has 6 - 3 = 3 more than grape

Do the first few questions of the practice worksheet together, one child explaining each step. Check for understanding before releasing the class to work alone.

Students complete the practice worksheet independently while you circulate and support.

Circulate and look for these, they are the usual sticking points:

• Making bars different widths, so a wide bar looks bigger than a taller thin one.
• Using an uneven or non-zero scale, which distorts the comparison.
• Misreading a bar that ends between gridlines by guessing instead of using the scale interval.
• Leaving off labels or a title, so the graph cannot be read.
• Reading between gridlines incorrectly when the scale counts by more than one.

Pull the class back together. Ask one child to explain bar graphs in their own words, pose a single check question everyone answers on a mini whiteboard, and name what you will build on next lesson.

Use the independent worksheet as the evidence. A child who can complete it accurately and explain one answer has met the objective; anyone who cannot needs the easier level and a short reteach next session.