The word "radiometer" is spelled as /reɪdiːˈɑːmɪtər/ in International Phonetic Alphabet. It is derived from the Latin word "radius" meaning ray and the Greek word "metron" meaning measure. The spelling of this word accurately reflects its pronunciation. The stress is on the second syllable, and each sound is articulated distinctly. The "e" after "d" is pronounced as a separate sound, making "radiometer" a six-syllable word. A radiometer is an instrument for measuring electromagnetic radiation, typically by means of a rotating wheel or paddle that is turned by the radiation.
The radiometer is a scientific device that measures radiant energy or radiation. It consists of a glass bulb that contains a partial vacuum, with a rotor inside that is capable of rotating freely. The rotor is typically composed of a set of light metallic vanes, which are white on one side and black on the other.
When exposed to a source of radiant energy, such as sunlight, the radiometer operates on the principle of thermal transpiration. As the radiant energy falls on the vanes, they absorb and emit heat, causing the air molecules surrounding the black sides to heat up more than the white sides. This temperature differential causes the gas molecules to move more rapidly on the black side and slightly slower on the white side, creating a net force imbalance. As a result, the rotor begins to spin.
The rotations per unit of time can be used to determine the intensity of the radiation. The radiometer is used in various scientific fields like atmospheric science, solar energy, and physics research to measure and study radiation levels and energy transfer. It offers a practical and visual approach to understanding and quantifying radiant energy.
The radiometer’s design and operation make it an effective tool for illustrating the principles of thermal transpiration and the conversion of energy from the electromagnetic spectrum to mechanical motion. Additionally, the device has applications in radiometry, where it is used to measure the power or intensity of electromagnetic radiation.
A device for determining the penetrative power of x-rays.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "radiometer" is derived from Latin and Greek roots. The Latin word "radius" means "ray" or "beam", and the Greek word "metron" means "measure". Therefore, "radiometer" combines these roots to form a word that essentially means "ray-measurer" or "beam-measurer". This is appropriate since a radiometer is a scientific instrument used to measure radiation, particularly in the form of electromagnetic waves.