Bar Charts and Pictograms

Why we use charts

Imagine asking 30 friends about their favourite pet and writing every answer in a long list. It would be hard to see which pet won. A chart turns that messy list into a clear picture, so you can compare groups at a glance. In this lesson we meet two of the most common: bar charts and pictograms.

It often starts with a tally chart, where we make a mark for each thing we count, crossing through every fifth mark to make groups of five. Counting in fives makes the totals quick to add up.

Pictograms

A pictogram shows data using pictures. Each picture stands for a number of items, and a key tells you how many.

Here is a pictogram of fruit sold in one morning. The key says 🍎 = 5 pieces of fruit.

Fruit	Pictures	Total
Apples	🍎🍎🍎🍎	20
Bananas	🍎🍎🍎	15
Oranges	🍎🍎	10

To find a total, multiply the number of pictures by the key. Apples show 4 × 5 = 20.

Half pictures

Sometimes a row needs half a picture to show an in-between number. If the key is 🍎 = 5, then half an apple means half of 5 = 2 and a half, which we round to a sensible value for the data. With a key of one picture = 10, a half picture means 5.

Worked example 1

Using the key 🍎 = 5, a row shows three and a half apples. How many fruits is that?

1. Three whole apples: 3 × 5 = 15.
2. The half apple: half of 5 = 2.5.
3. Total: 15 + 2.5 = 17.5, so we would record about 17 or 18 fruits.

Bar charts

A bar chart shows data as bars. The longer or taller the bar, the bigger the number. Bars can stand up (vertical) or lie down (horizontal). Every bar chart needs:

• a title that says what it is about,
• labels on both axes (the side and the bottom),
• a scale of evenly spaced numbers up one side.

The most important habit is to check the scale. The lines might go up in 1s, but they could just as easily go up in 2s, 5s or 10s. Reading the scale wrongly gives every answer wrong. This is the same skill you practised in Reading Scales and Measuring.

Worked example 2

A bar chart shows how children travel to school. The scale goes up in 2s: 0, 2, 4, 6, 8, 10.

Way to travel	Bar reaches	Number of children
Walk	5th line	10
Car	3rd line	6
Bike	2nd line	4
Bus	1st line	2

To read "Car": the bar reaches the 3rd line, and counting up in 2s gives 2, 4, 6. So 6 children come by car.

Asking questions about charts

Charts are made to be questioned. Useful questions include:

• Which is the most popular? Look for the longest bar or the most pictures. (Walking, with 10.)
• Which is the least popular? Look for the shortest bar. (Bus, with 2.)
• How many more? Subtract one value from another. Walk − Bike = 10 − 4 = 6 more children walk than bike.
• How many altogether? Add all the values. 10 + 6 + 4 + 2 = 22 children.

Worked example 3: a "how many more" problem

Using the travel chart above, how many more children walk than come by bus?

1. Children who walk: 10.
2. Children by bus: 2.
3. Difference: 10 − 2 = 8 more children walk.

Drawing your own bar chart

To turn a tally into a bar chart:

1. Draw two lines for the axes, like a big letter L.
2. Choose a scale that fits your biggest number, going up in equal steps.
3. Label the bottom with the groups and the side with numbers.
4. Draw each bar to the right height, leaving gaps between them.
5. Add a clear title.

Why charts beat lists

Why turn numbers into pictures at all? Because our eyes are very good at comparing sizes but slow at comparing numbers in a list. On a bar chart, the tallest bar jumps out instantly — you spot the winner without reading a single number. A chart packs lots of information into a shape you can understand in a second. That is the real power of data handling.

Try it yourself

Ask ten people for their favourite season (spring, summer, autumn, winter).

1. Make a tally chart as you ask.
2. Turn it into a pictogram using the key ☀️ = 2 people.
3. Then draw a bar chart of the same data.
4. Write two questions about your chart, such as "which season is most popular?"

Well done!

You can now read and draw bar charts and pictograms, use a key and scale, and answer questions about data. Take the next step with Reading Charts and Graphs, which brings together even more ways to show data.