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Radiometer – MAS 4121
A partially evacuated bulb with four coloured vanes. Light falling on the vanes cause them to rotate The Radiometer is a deceptively simple device providing an intriguing introduction to the study of gases, molecular motion, and thermodynamics. An evacuated glass bulb encloses a rotating shaft with vanes painted black on one side, silver on the other. Light energy differentially warms the vanes’ flat surfaces, imparting energy to the gas molecules which “kick” the vanes into a rapid rotation. Radiometers may also be described as solar radiometers or UV radiometers. |