section_path: Uses
section_name: Uses
paragraph_text: Uses
  
  The total amount of artificial light (especially from street light) is sufficient for cities to be easily visible at night from the air, and from space. External lighting grew at a rate of 3–6 percent for the later half of the 20th century and is the major source of light pollution that burdens astronomers and others with 80% of the world's population living in areas with night time light pollution. Light pollution has been shown to have a negative effect on some wildlife.
  
  Electric lamps can be used as heat sources, for example in incubators, as infrared lamps in fast food restaurants and toys such as the Kenner Easy-Bake Oven.
  
  Lamps can also be used for light therapy to deal with such issues as vitamin D deficiency, skin conditions such as acne and dermatitis, skin cancers, and seasonal affective disorder. Lamps which emit a specific frequency of blue light are also used to treat neonatal jaundice with the treatment which was initially undertaken in hospitals being able to be conducted at home.
  
  Electric lamps can also be used as a grow light to aid in plant growth especially in indoor hydroponics and aquatic plants with recent research into the most effective types of light for plant growth.
  
  Due to their nonlinear resistance characteristics, tungsten filament lamps have long been used as fast-acting thermistors in electronic circuits. Popular uses have included: