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Equation 11 · Part 1 · Einstein's Random Walk and the Mathematics of Genetic Drift

Symbol D

DD
DD

What this part means

D is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

D is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

where R is the gas constant, T the absolute temperature, and N Avogadro’s number [ 1 ] . That last dependency was the trap door: if D could be read off a microscope by timing how far a particle wandered, and every other term in the equation was already known independently, then watching one particle jiggle became a way to count atoms.

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the surrounding passage

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