Idea 14of 22Builds onSame numbers, different pictures
Bars need a scale that starts at 0
Why should a bar graph's scale start at 0?
Today you'll discover
- what a scale from 40 cuts off
- what a zigzag on the scale means
- when zooming in is fair
Think firstLook at the bottom of the scale
Where does this graph's scale start?
Decide first, then press Next. Find the lowest number on the scale.
The garden bar graph with its scale from 40 to 48. The lowest number, 40, is ringed, and a note says the bottom 40 of every bar is cut off. Then a line graph of a fever from 37 to 39 degrees, its scale starting at 35 with a ringed zigzag at the bottom. Then the garden bars with the scale from 0. The last step shows Bike-a-thon bars with the scale starting at 80.
See the whole ideathe big idea and the key word, in one place
The big idea
Bars must start at 0, because a bar's length shows its amount.
Easy to get wrongA bar scale that starts above 0 with no zigzag makes small gaps look huge. Read the numbers, not the heights.
Zoomed on purposeScientists zoom in to show small changes, like a fever. A fair zoom shows a zigzag and prints the numbers.
Key word
- broken axis
- a scale that skips from 0 up to a bigger number, shown fairly with a zigzag
Ready to use it?
- Find where a graph's scale starts.
- Say whether a zoomed graph is fair.