Graph Maker – Picture, Bar and Line Graphs

Why Make Graphs, Not Just Read Them

Most children meet graphs as something to read: a bar graph in a textbook, followed by questions. That is useful practice, but it skips the most important part. A graph is a way of answering a question with data, and children understand graphs far better once they have chosen the data, decided how to show it, and seen how a different scale or a different kind of graph changes the picture. This page lets them do all of that in a few taps, and then turns their graph into questions so they can practise the reading side as well.

Making graphs also builds number sense. Choosing a scale means counting in twos, fives or tens. Reading a bar that stops halfway between two lines means thinking about halves. Working out “how many more” is subtraction, “how many altogether” is addition, and a picture graph where each picture stands for 2 is multiplication and division in disguise.

How to Use This Page

1. Choose the data. Pick one of the ready class data sets, or choose My own data and type in names and numbers. You can have from 2 to 10 rows. Change the graph title and the titles of the two sides (the axes) to match.
2. Choose the graph. A picture graph shows each amount as a row of pictures, with a key such as 1 picture = 2 pupils. A bar graph can have bars going up or across. A line graph joins the points with a line, for data that changes over time.
3. Choose the scale. Auto picks a sensible step, such as counting in 2s, 5s or 10s. My own step lets you choose, which is a good way to see why some scales are easier to read than others.
4. Answer the questions. The page writes questions from your data: reading a value, finding the most and the least, how many more, the total, and for data over time, the difference between two days and when it increased the most. Press Check after each one.
5. Save or print. Save the graph as a picture for a project or a slide, or print it with the questions and an answer key on a second page.

Picture Graphs and the Key

Picture graphs (sometimes called pictograms) are where most children in Singapore start, in P1 and P2, before moving on to keys in P3. At first each picture stands for one thing, and reading the graph is just counting. The big step is the key: when one picture stands for 2 pupils, a row of 4 pictures means 8 pupils, and half a picture means 1. Try the favourite fruit data with a key of 1, then 2, then 5, and talk about which is easiest to draw and which is easiest to read. With a key of 5 the rows are short, but most amounts become parts of pictures, which are hard to read exactly. That trade-off is the real lesson of the key, and the page points out when an amount does not fit neatly.

Bar Graphs and Choosing a Scale

A bar graph replaces the rows of pictures with bars measured against a scale. The scale must start at 0 and go up in equal steps, and every step should be the same size on the page; children sometimes forget both. Here the numbers side always starts at 0 and the gridlines are evenly spaced, so the length of each bar is a fair picture of its value. Let your child try My own step with a step of 1 for the rainfall data and see the graph fill up with lines, then a step of 50 and see how much easier it is to read. A good scale has between about five and ten steps. Bars can go up or across; both are correct, and across is handy when the names are long.

Bars do not have to stop on a gridline. A bean plant that is 4.5 cm tall has a bar that ends halfway between 4 and 5. Reading these values, and estimating a bar that ends between two lines, is an important part of P3 and P4 data work.

Line Graphs: Change Over Time

A line graph is the right choice when the names along the bottom are times, such as days, weeks or months, and the question is how something changes. The temperature over a week and the height of a bean plant are good examples. The line between two points shows whether the value went up or down, and how steeply. Ask questions such as “Between which two days did the plant grow the most?” and show that the answer is where the line is steepest. A line graph for favourite fruit, on the other hand, makes no sense, because there is nothing “between” apples and bananas; the page will still draw it, but it points this out. Line graphs are taught in the upper primary years in Singapore, and they appear often in Science as well as in Mathematics.

The Questions the Page Asks

The questions are made from your data each time it changes, and the answers are worked out from the numbers, so they are always right for the graph you can see. You will meet:

• Reading a value: How many pupils chose mango? How tall was the plant on Day 4?
• Counting pictures: in a picture graph, how many pictures are drawn for a row, using the key.
• Most and least: Which fruit is the most popular? Which month had the least rain? These are only asked when there is one clear answer.
• Comparing: How many more chose apple than durian? What is the difference between the temperatures on two days?
• Totals: How many pupils were asked altogether? What was the total rainfall?
• Change over time: Between which two days did the temperature rise or fall the most?

Press New questions for a different set from the same graph.

Ideas for Home and the Classroom

• Run a survey. Ask the family or the class a question with four or five answers: favourite colour, how you get to school, favourite fruit. Tally the answers, type them in and make a picture graph and a bar graph of the same data.
• Grow something. Plant a bean in a cup and measure it every day. After a week or two you have real data for a line graph, with numbers like 3.5 cm that make good practice.
• Keep a weather diary. Record the temperature or whether it rained each day for a week and graph it.
• Swap roles. One child makes a graph and writes three questions about it; another answers them. Then check with the questions the page writes.
• Spot the bad graph. Choose a step of 3 or 7 and ask why it is hard to read. Choose a line graph for pets and ask what the line between cats and dogs could mean.

How This Fits the Singapore Syllabus

Picture graphs come first, in the lower primary years, with each picture standing for one item and then, by P3, for more than one. Bar graphs with a scale are a main part of P3 and P4 data analysis, including reading values, comparing bars and solving word problems from the graph. Line graphs follow in the upper primary years, alongside tables and pie charts. The levels in schools vary a little, so use the graph types that match what your child is learning now, and let them explore the others when they are curious.

Nothing to Install, Nothing Uploaded

The graph maker runs entirely in your browser on any phone, tablet or computer, with no account and no download. Your data and choices are kept only in your own browser, so your graph is still there next time; nothing is sent to us, and saved pictures go straight to your own device.