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Bar graphs

Interpret and present discrete and continuous data using appropriate graphical methods, including bar charts and time graphs

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What a learner can do afterwards

  • Read a time graph showing temperature changes over a day
  • Present data about plant growth over weeks as a time graph
  • Explain the difference between a bar chart (discrete) and a time graph (continuous)

The lesson

A bar chart uses bars to compare separate groups, like how many children like each colour. Each bar's height shows a number. Taller bars mean bigger numbers.

Red5Blue8Green3Yellow6
Blue's bar is the tallest, so blue got the most votes.

A time graph is different. It shows something changing over time, like the temperature during a day. Instead of separate bars, you draw a line that moves up and down as the number changes.

Try it together

A gardener measures her plant every week. Week 1 it is 2 cm, week 2 it is 5 cm, week 3 it is 9 cm. She draws a time graph with a line that climbs higher each week, showing the plant growing.

Good to know

Ask yourself: are these separate groups, or is something changing over time? Separate groups, like favourite colours, need a bar chart. Change over time, like temperature or growth, needs a time graph.

Bar charts compare separate groups with bars, and time graphs show change over time with a connecting line.

Watch it

Where it sits

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.

Bar graphs · Mathematics, ages 8 to 9 · LightMySky