https://padlet.com/dkt205775/sorcesoflight Made with a bold sensibility en-us 2017-02-24 12:52:20 UTC 2024-05-24 20:10:05 UTC hello@padlet.com dkt205775 https://padlet.com/dkt205775/sorcesoflight/wish/156002544 The sun is the most important sources of light. The stars and moon are also natural forms of light. Artificial light is light made by humans, for example candles, fire and oil lamps. ... The light bulb, neon light and fluorescent tube are types of electric light.]]> 2017-02-24 12:55:30 UTC https://padlet.com/dkt205775/sorcesoflight/wish/156002544 dkt205775 https://padlet.com/dkt205775/sorcesoflight/wish/156003752 1) Light is a form of energy. When something burns it often gives off light energy as well as heat energy. The sun, for example, is a ball of burning gases which give off lots of light. The earliest form of light that humans used was the light created from burning wood. Today we get light from many different sources both natural and artificial.

2) Light waves usually travel in straight lines called rays of light. Each light wave is made up of different wavelengths which make different colours of light. Light waves may be reflected (bounce off) or refracted (change direction) and may change speed depending on the material they are passing through.

]]> 2017-02-24 13:03:21 UTC https://padlet.com/dkt205775/sorcesoflight/wish/156003752 dkt205775 https://padlet.com/dkt205775/sorcesoflight/wish/156004496 is the production and emission of light by a living organism. It is a form of chemiluminescence. Bioluminescence has arisen over forty times in evolutionary history. luciferase - based systems are used in genetic engineering and for biomedical research. Other researchers are investigating the possibility of using bioluminescent systems for street and decorative lighting, and a bioluminescence plant has been created.]]> 2017-02-24 13:07:39 UTC https://padlet.com/dkt205775/sorcesoflight/wish/156004496 dkt205775 https://padlet.com/dkt205775/sorcesoflight/wish/156006482 The decay of this excited state to a lower energy level causes light emission. In theory, one photon of light should be given off for each molecule of reactant. This is equivalent to avogadro's number of photons per mole of reactant. In actual practice, non-enzymatic reactions seldom exceed 1% Q_C, quantum effciency. It is the antithesis of a photochemical reaction, in which light is used to drive an endothermic chemical reaction. Here, light is generated from a chemically exothermic reaction. A standard example of chemiluminescence in the laboratory setting is the luminol test. ... A light stick emits light by chemiluminescence.]]> 2017-02-24 13:18:17 UTC https://padlet.com/dkt205775/sorcesoflight/wish/156006482 dkt205775 https://padlet.com/dkt205775/sorcesoflight/wish/157118150 . The light bulb is supplied with electric current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides mechanical support and electrical connections Objections to replacement of incandescent lamps for general lighting mainly include the higher purchasing cost of alternative light bulbs. To mitigate the effects of these concerns, various programs have been put in place ranging from subsidies for lamps to improved standards for measurement of performance and for labelling products. Manufacturers develop fluorescent lamps with reduced mercury content compared to original designs, and recycling programs are intended to prevent mercury release. New lamp types offer improved starting characteristics, and dimmable types are available.]]> 2017-03-01 18:05:54 UTC https://padlet.com/dkt205775/sorcesoflight/wish/157118150 dkt205775 https://padlet.com/dkt205775/sorcesoflight/wish/157298254 Everyday examples of phosphorescent materials are the glow-in-the-dark toys, stickers, paint, and clock dials that glow for some time after being charged with a bright light such as in any normal reading or room light. Typically, .the glow slowly fades out, sometimes within a few minutes or up to a few hours in a dark room.In simple terms, phosphorescence is a process in which energy absorbed by a substance is released relatively slowly in the form of light. This is in some cases the mechanism used for "glow-in-the-dark" materials which are "charged" by exposure to light. Unlike the relatively swift reactions in fluorescence, such as those seen in a common fluorescent tube, phosphorescent materials "store" absorbed energy for a longer time, as the processes required to re-emit energy occur less often.]]> 2017-03-02 12:58:07 UTC https://padlet.com/dkt205775/sorcesoflight/wish/157298254 dkt205775 https://padlet.com/dkt205775/sorcesoflight/wish/157612471 . Luminescence is a process of giving off light without obtaining or generating heat. This can be caused by chemical or biochemical reactions, activity of subatomic particles, radiation or stress on a crystal. Chemoluminescence - This process creates light through a chemical reaction. Common applications are glow sticks (cyalume sticks) and the forensic application for locating blood using luminol. ]]> 2017-03-03 14:14:19 UTC https://padlet.com/dkt205775/sorcesoflight/wish/157612471