Drawing to scale
Design & Technology · Key Stage 2 · The School
What a scale means
A SCALE compares a drawing's size to the real size. A scale of 1:2 means the drawing is half the real size. One unit on paper stands for two real units. A scale of 2:1 means the drawing is twice the real size. This is useful for something too small to draw clearly at full size. Maps and model kits use scales too, written the very same way.
Drawing at half size
A real box is 20 cm by 10 cm. Drawn at 1:2, it becomes 10 cm by 5 cm. Every measurement is halved, not just some of them. Halving only one side would turn the rectangle into the wrong shape entirely. Checking every measurement, not just the biggest one, is what keeps the shape true.
Why scale drawings are useful
A real product is often too big to draw clearly at its true size. Sometimes it is too small instead. A scale drawing keeps every part in the right proportion to every other part. The true shape stays clear, whatever size the paper is.
A real shed is 240 cm wide, 200 cm deep and 220 cm tall. It is drawn at a scale of 1:20. Every measurement is divided by 20. That gives 12 cm wide, 10 cm deep, 11 cm tall. The drawing now fits easily on a sheet of paper. Every part is still in the right proportion to every other part. The door still looks the right size next to the roof. It is simply twenty times smaller.