42 Many other inventors developed their versions of light bulbs. Search the Internet to find some of them. Only 5% of the electricity employed to light up an incandescent bulb is converted into light, while 95% becomes heat. LIGHTING Among the applications of electricity, one of the most common is lighting. Lighting in a home can account for up to 20% of energy consumption; for this reason, research has been concentrated on producing new types of bulbs that can last longer and consume less. bulbs, but it uses 25-30% of the power required by them and lasts 8-15 times longer. As it contains toxic mercury, many countries have created dedicated areas for its collection after use, as it cannot be disposed of together with common garbage. Incandescent bulbs The invention of the first electrical lamp is generally attributed to Thomas Edison in 1879 . This type of lamp, called the incandescent bulb, was made up of a carbon filament inserted into a vacuum glass. When electricity reached the filament, it became incandescent and glowed, producing light. LED bulbs An LED light bulb produces light using light-emitting diodes that are made up of semiconducting materials. When electricity flows through a LED, the electrons combine with the semiconductor emitting photons that produce light. LED lamps are the most expensive but also the most energyefficient type of lamps available and have a life many times longer than incandescent lamps. In OLED (Organic LED) light bulbs, the light emitting material is a film of organic compound. Halogen bulbs In the following years, the carbon filament of the incandescent bulb was substituted with a tungsten one inserted into an envelope containing a mixture of halogen gases. The electricity arriving to the bulb makes tungsten evaporate, but its reaction with halogen gases prevents it from blackening the inner surface of the lamp, increasing its efficiency. collection: raccolta disposed of: gettato via envelope: involucro garbage: immondizia to glow: splendere inner: interno vacuum: vuoto 98 ELECTRICITY CFLs CFLs (Compact Fluorescent Lightbulbs) employ a technology that depends on a chemical reaction inside a glass tube to create light. This chemical reaction involves gases and mercury vapours, which produce an invisible UV light. The UV light strikes a chemical coating inside the glass tube, emitting white fluorescent light. A CFL bulb has a higher price than incandescent