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A crescograph is a device for measuring growth in
A crescograph is a device for measuring growth in plants
Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...
. It was invented in the early 20th century by Sir Jagadish Chandra Bose
Sir Jagadish Chandra Bose
(;, ; 30 November 1858 – 23 November 1937) was a biologist, physicist, Botany, botanist and an early writer of science fiction. He was a pioneer in the investigation of radio microwave optics, made significant contr ...
.
The Bose crescograph uses a series of clockwork gears and a smoked glass
Smoked glass is glass held in the smoke of a candle flame (or other inefficiently burning hydrocarbon) such that one surface of the sheet of glass is covered in a layer of smoke residue. The glass is used as a medium for recording pen traces in sc ...
plate to record the movement of the tip of a plant (or its roots). It was able to record at magnifications of up to 10,000 times through the use of two different levers. One lever records at 100 times magnification while the other lever takes that image and records at another 100 times magnification. Marks are made on the plate at intervals of a few seconds, demonstrating how the rate of growth varies under varying stimuli. Bose experimented with temperature, chemicals, gases, and electricity.
The electronic crescograph plant movement detector is capable of measurements as small as 1/1,000,000 of an inch. However, its normal operating range is from 1/1000 to 1/10,000 of an inch. The component which actually measures the movement is a differential transformer along with a movable core hinged between two points. A micrometer Micrometer can mean:
* Micrometer (device), used for accurate measurements by means of a calibrated screw
* American spelling of micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; ...
is used to adjust and calibrate the system. It can record plant growth, magnifying a small movement as much as 10,000,000 times. This machine is highly sensitive; Bose padded the legs of the table on which the Crescograph is being used with India-rubber sponges. This negated any vibration which could affect results.
References
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