The diameter of a hair is about 9.33 times the characteristic size of a red blood cell. Selected basis: a representative value for Red blood cell; an example for Hair; approximate values.
The ring marks the true-scale position of a red blood cell; it does not show its width. Only the inset is enlarged (×59.7).
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions. Horizontal rulers compare the selected spans; vertical brackets also identify height on the artwork.
7.5 µm - Characteristic size; representative.
A red blood cell is a specialised blood cell that transports oxygen using haemoglobin. Mature human red blood cells are flexible, disc-shaped cells.
A chosen 7.5 µm human red-blood-cell diameter. Real cells vary and deform.
University of Utah — Cell size and scale70 µm - Diameter; example.
A hair is a slender strand of protein that grows from the skin of humans and other mammals.
A 70 µm diameter example; hair thickness varies.
Defined examples — our methodology
There’s always another scale
MicroscopicRed blood cell7.5 µmA red blood cell is a specialised blood cell that transports oxygen using haemoglobin.
PeopleHair70 µmA hair is a slender strand of protein that grows from the skin of humans and other mammals.
Living thingsHoneybee1.5 cmA honeybee is a social insect that lives in a colony and gathers nectar and pollen from flowers.
Living thingsSmall ant5 mmAn ant is a social insect that lives in an organised colony, usually with workers, a queen and specialised roles.
Everyday thingsUS quarter2.426 cmA US quarter is a coin worth twenty-five cents, commonly used in United States currency.Side by side
Illustrative artwork · not to scale
Illustrative artwork · not to scale
Illustrative artwork · not to scale
Illustrative artwork · not to scaleGot a good eye for scale?