Dictionary > Optical density

Optical density

Definition
noun
(1) The measure of transmittance of an optical medium for a given wavelength. The higher the OD the lower the transmittance, the higher protection factor by a filter (e.g. goggles, viewing windows, etc.).
(2) The measure of the amount of light absorbed by a suspension of bacterial cells or a solution of an organic molecule with the use of a colourimeter or spectrophotometer.
Supplement
In microbiology, the values can be used to measure turbidity, which in turn is used to estimate the number of bacteria (or concentration of molecules like proteins) in a solution.
Abbreviation: OD
Synonym: absorbance.

See also: absorption.


You will also like...

Adaptation Tutorial
Adaptation Tutorial

Adaptation, in biology and ecology, refers to the process or trait through which organisms or the populations in a habit..

Schematic diagram of bacterial lactose operon
Gene Action – Operon Hypothesis

Learn how the way genes control and determine every aspect of the body. This lesson uses lac operon as an example. ..

..

An artistic depiction of Dunkleosteus fish
Fish

The sea was teeming with life. Eventually, through reproduction and continued variation, fish came about. There are over..

Genetics and Evolution
Genetics and Evolution

Humans are diploid creatures. This means that for every chromosome in the body, there is another one to match it. Howeve..

Endemic Flora of New Zealand
New Zealand’s Unique Flora

If New Zealand has lots of unique animals, it's also got a whole lot of unique plants. Find out more about some of them,..

Birth of a Human Baby
Birth of a Human Baby

Following nine months inside the mother's womb is the birth of the baby. Know the different stages of the birthing proce..