ACARA v9 CONTENT DESCRIPTION “construct and use representations, including tables, simple column graphs and visual or physical models, to organise data and information, show simple relationships and identify patterns”
Builds on counting and sorting things into groups. Here a pile of numbers becomes organised: first into a tidy table, then into a simple column graph. A good representation does a job for you. It shows a relationship and helps a pattern stand out.
From a pile of counts to a tidy table
Imagine you watched a bird feeder and counted how many birds visited each day for a week. If you just keep the numbers in your head, they get jumbled. A table fixes that. You write each day in one column and the count for that day next to it. Now every number has a home, and nothing is lost. A table is your first and tidiest representation of the data.
Put the counts in a table, then draw the graph
Here are the bird counts for six days. Look at the table, then switch to the column graph to see the same numbers as bars.
Same data, two pictures. The table keeps every number neat in a row. The column graph turns each count into a bar, and the bars get taller from Monday to Saturday, so the pattern of rising visits is easy to see at a glance.
Reading the relationship in the bars
A column graph is more than a pretty picture. The height of each bar is the count for that day, so the tallest bar is the day with the most birds. When you line the bars up, you can read a relationship: as the days go on, the bars climb, which means more birds visited as the week went on. Spotting this kind of simple relationship is exactly what a graph is for.
Find the count that breaks the pattern
On another week the bird counts climbed steadily, except one day. The bars and points rise together, but one reading does not fit the climb. Click the one that breaks the pattern.
Click the point that does not fit the pattern of the others.
Reading the graph correctly
A graph only helps if you read it the right way. A correct reading uses the bars to answer a question, such as which day had the most birds, or whether the counts went up or down. Things like the colour of the bars or which day you like best are not what the data shows. Telling a true reading apart from a guess is how you turn a graph into real evidence.
Which sentences correctly read the graph?
The column graph shows birds counted each day, rising from Monday to Saturday with Saturday the tallest bar. Decide which statements are correct readings of that graph.
Claim: The column graph shows the bird counts rising across the week, with Saturday the tallest bar.
Saturday has the tallest bar, so Saturday had the most bird visits.
The bars get taller from Monday to Saturday, so visits went up across the week.
Monday has the shortest bar, so Monday had the fewest visits.
The bars are a nice shade of blue.
Saturday must be everyones favourite day of the week.
Decide whether each statement is evidence for the claim, or not.
Why it matters
Tables and column graphs are tools you will use again and again. Putting data into a table keeps it organised, and turning it into a graph lets a relationship and a pattern show themselves. Learning to build these representations, and to read them honestly, is how a young scientist makes sense of what they have counted and measured.
Quick self-check
1. You counted how many cars went past each day. What is the best first step to keep the counts tidy?
2. A column graph helps you because it...
3. On your graph the bars get taller each day. This pattern shows...
4. One bar is much shorter than all the others around it. This odd value...
5. Which sentence correctly reads a column graph of daily counts?