Which of the following parts of the sunlight makes the solar cooker hot?
(1) Ultraviolet
(2) Red light
(3) Infrared
(4) Cosmic rays
Answer: (3) Glass transmits visible light but blocks infrared thermal radiation from escaping. This amplifies the heat-trapping effect. A solar cooker, or solar oven, is a device that uses the energy of direct sunlight to heat food or drink to cook it or sterilize it. The vast majority of the solar cookers presently in use are relatively cheap, low-tech devices. Because they use no fuel and cost nothing to operate, many nonprofit organizations are promoting their use worldwide to help reduce fuel costs for low-income people, reduce air pollution and slow deforestation and desertification, caused by the use of firewood for cooking. Solar cooking is a form of outdoor cooking and is often used in situations where minimal fuel consumption is important, or the danger of accidental fires is high.
