🖍️ How to draw a bar graph by hand

Bars or a line?

Your project page already says which graph to draw. The rule is: bars for separate things, a line for a number that goes up in steps. Of the 118 projects, 80 draw bars and 38 draw a line.

Floors, wing shapes and boat shapes are separate things: there's nothing halfway between carpet and a towel, so each gets its own bar. Some that draw bars:

• Paper airplane wing shapes: one bar each for narrow dart; wide glider; long straight wings.
• Bouncing balls on different floors: one bar each for carpet; hard floor (wood or tile); a folded towel.
• Paper bridge shapes: one bar each for flat; folded like a fan; rolled into tubes.
• Straw rocket nose shapes: one bar each for flat, folded shut; short pointed cone; long pointed cone.

String lengths and spoonfuls are numbers on a line: there's a 30 between 20 and 40, so joining the points makes sense. Some that draw a line:

• Ramp height and toy cars: 1 book high, 2 books high and 3 books high.
• Parachute size and fall time: 20 cm square, 30 cm square and 40 cm square.
• Pendulum length and swings: 20 cm, 40 cm and 60 cm.
• Rubber band stretch: 10 pennies, 20 pennies, 30 pennies and 40 pennies.

Draw the two lines first

• Use squared paper, or the graph paper at the bottom of the results sheet.
• Draw a line along the bottom and a line up the left side. These two lines are called the axes.
• Along the bottom, write what you changed. For the boats, that's the boat shape.
• Up the side, write what you measured, with its unit: for the boats, pennies carried.

Pick a scale that fits

The scale is how much each square stands for. Find your biggest mean, then count up by an easy number (1, 2, 5 or 10) until you pass it. Always start at 0, and keep the squares even all the way up.

Here are some made-up boat means: flat raft 30 pennies, square box 75, round bowl 55. The biggest is 75, so count by 10s: 0, 10, 20, all the way to 80. That's 8 squares tall, which fits nicely on the page.

Draw the bars

• Space the bars evenly along the bottom, with a gap between each one.
• Make every bar the same width. Two squares wide is good.
• Draw each bar up to its mean. A mean of 55 sits halfway between 50 and 60.
• Write the level under each bar, and the number on top if you like.
• Colour the bars in, then give the graph a title. Your question makes a good one.

Draw one bar for each level, as tall as its mean, not one bar for every try. At 1st to 3rd grade, a simple bar graph, or even a picture, is plenty.

Drawing a line graph instead

If your project says line, the first steps are the same. Then, instead of bars, put a dot at each level's mean and join the dots with a ruler. Space the levels along the bottom by their numbers, so 20, 40 and 60 sit evenly apart.

From 7th grade, a second variable means two lines, or two sets of bars, on one graph. Give each its own colour and add a little key in the corner.

Your graph goes in the results section of your board, right beside the table.