Scale (ratio)
The scale of a map shows the ratio between the distances on the map and the corresponding distances in reality. For example, a map of scale 1:50,000 shows a distance of 50,000 cm (or 500 m) as 1 cm on a map. A 1:25 scale model of a building with a height of 30 m has a model height of 1.20 m.
When a drawing or model or photograph of an object is larger or smaller than the original, the scale represents how much the object has been "grown" or "shrunk".
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Polytene_chromosomes_%2826_2_97%29_Salivary_glands_of_nonbiting_midges_larvae_%28Chironomidae%29.jpg/250px-Polytene_chromosomes_%2826_2_97%29_Salivary_glands_of_nonbiting_midges_larvae_%28Chironomidae%29.jpg)
Scale bars[change | change source]
Scale bars for microscopic or unusual objects are necessary. They help readers to understand the diagram.