====== Infrared ======
When any type of light is absorbed by an object, that object will be heated. The infrared light from an electric heater feels hot for two reasons:  ((Amasci: http://amasci.com/miscon/miscon4.html#heat)) 
  - because surfaces seem black to infrared (IR) light
  - because the infrared light (IR) is extremely bright light. 


{{ youtube>xZVPhWxC9V8?640x360 |Infrared Radiation  - How it works}}
=== Video 1. Infrared Radiation - How it works ===
  * **IF YOUTUBE FAILS, TRY VIEWPURE:[[http://viewpure.com/xZVPhWxC9V8|Infrared Radiation - How it works]]**

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=== Introduction To The Physics of Infrared & Radiation ===
{{ youtube>hPJPbbT1TsM?640x360 |Infrared & The Radiation Spectrum}}
=== Video 2. Infrared & Radiation) ===
  * **IF YOUTUBE FAILS, TRY VIEWPURE: [[http://viewpure.com/hPJPbbT1TsM| Introduction To The Physics of Infrared & Radiation]]**

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An infrared heater or heat lamp is a body with a higher temperature which transfers energy to a body with a lower temperature through electromagnetic radiation. No contact or medium between the two bodies is needed for the energy transfer. Infrared heaters can be operated in vacuum or atmosphere. Source: https://en.wikipedia.org/wiki/Infrared_heater

Heat lamps are commonly used in shower and bathrooms to warm bathers and in food-preparation areas of restaurants to keep food warm before serving. They are also commonly used for animal husbandry. Lights used for poultry are often called brooding lamps. Aside from young birds, other types of animals which can benefit from heat lamps include reptiles, amphibians, insects, arachnids, and the young of some mammals.

The first experiment to test the heating efficiency of infrared used a prism to catch the sunlight and direct and disperse the colors down onto a table, the second was a small panel of cardboard with a slit wide enough for only a single color to pass through it and finally, three mercury-in-glass thermometers. Through his experiment Herschel found that red light had the highest degree of temperature change in the light spectrum, however, infrared heating was not commonly used until World War II. 

After the war, infrared was used extensively in the motor industry - Why?

** Fig 1. Anyone for a nice hot kebab? **


{{ :learn:heat:infrared:infrared-kebab.jpg|Infrared kebab cooker}}
IR heaters can satisfy a variety of heating requirements, including:
  * Extremely high temperatures, limited largely by the maximum temperature of the emitter
  * Fast response time, on the order of 1–2 seconds
  * Temperature gradients, especially on material webs with high heat input
  * Focused heated area relative to conductive and convective heating methods
  * Non-contact, thereby not disturbing the product as conductive or convective heating methods do

Thus, IR heaters are applied for many purposes including:
  * Heating systems
  * Curing of coatings
  * Plastic shrinking
  * Plastic heating prior to forming
  * Plastic welding
  * Glass & metal heat treating
  * Cooking
  * Warming suckling animals or captive animals in zoos or veterinary clinics
  * Hot Yoga fitness classes to mitigate respiratory issues posed by convection heating[16]

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