Lightningthe visible discharge of electricity that occurs when a region of a cloud acquires an excess electrical chargeeither positive or negative, that is sufficient to break down the resistance of air.
A brief description of lightning follows. For a longer discussion of lightning within its meteorological contextsee thunderstorm electrification in the article thunderstorm.
Lightning is usually associated with cumulonimbus clouds thundercloudsbut it also occurs in stratiform clouds layered clouds with a large horizontal extentin snowstorms and dust storms, and sometimes in the dust and gases emitted by erupting volcanoes. During a thunderstorm, lightning can occur within the cloud, between clouds, between the cloud and the air, or between the cloud and the ground.
Lightning occurs when regions of excess positive and negative charge develop within the cloud. Typically, there is a large volume of positive charge in the upper regions of the cloud, a large negative charge in the centre, and a small positive charge in the lower regions. These charges reside on water drops, ice particles, or both.
Cloud-to-ground lightning is initiated by a preliminary breakdown process within the cloud, typically between the centre region of negative charge and the small positive charge below it. This process creates a channel of partially ionized air—air in which neutral atoms and molecules have been converted to electrically charged ones. Next, a stepped leader initial lightning stroke forms and propagates downward, following channels created by the preliminary breakdown process.
The leader is highly branched in the direction of its propagation. Most leader channels are negatively charged. When the stepped leader nears the ground, an upward, connecting discharge of opposite polarity rises and meets it at a point typically about 30 metres feet above the ground. When the junction is complete, the cloud is effectively connected to the ground, and a very bright return stroke propagates back to the cloud at a speed about one-third the speed of lightfollowing the leader channel.
A typical lightning flash to the ground contains three or four leader-return stroke sequences in rapid succession. Occasionally, when there is a strike to a mountain or tall building, the first leader will start at the ground and propagate upward.
The potential difference between cloud and ground is of the order of 10 to million voltsand the peak currents in return strokes to negative leaders are typically about 30, amperes. The entire process is very rapid; the leader stroke reaches the ground in about 30 milliseconds, and the return stroke reaches the centre of the cloud in about microseconds.
Thunder is produced by rapid heating of the air in the lightning channel and a consequent increase in air pressure.
The over-pressure causes the channel to expand at supersonic speeds, which ultimately produces a sound wave heard as thunder. The claps, rolls, and rumbles that characterize the sound of thunder are produced by the complex geometry and tortuosity of the lightning channel as well as the effects of the atmosphere and local topography on sound propagation.
Lightning is a significant weather hazard and occurs at an average rate of 50 to discharges per second worldwide. Lightning rods and metallic conductors can be used to protect a structure by intercepting and diverting the lightning current into the ground as harmlessly as possible. When lightning is likely to occur, people are advised to stay indoors or in a car, away from open doors and windows, and to avoid contact with any electrical appliances or plumbing that might be exposed to the outside environment.It stops making things lighter and brighter and it turns into a natural phenomenon many people find scary.
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We use the verb lighten in two senses—one has to do with color and the other refers to weight. When we talk about changing the appearance of something by giving it a lighter color, we can say we are lightening it: Adding mirrors to a room can have a lightening effect. In the other sense, we can use the verb lighten to say that we are making something less heavy, literally or figuratively: Paul rushed and picked up the other end of the table, lightening the load for Peter. Joan spent the night lightening the mood with her jokes.
Lightning is the electrical discharge that happens during an electrical storm. The Smithsonian Once lightning hits, the electromagnetic waves travel through two copper coils at right angles, inducing a current. Wired When New York rapper Azealia Banks took to Facebook this month to defend her use of skin-lightening products, she came armed with claims of hypocrisy. Quartz This flying radio could deliver secure communication with greater range and flexibility while lightening the load for troops by reducing the burden of radio carrying.
Fox News. Marko Ticak. Lightening is the present participle of the verb lighten. Lightning is the electrical discharge that happens during storms. Adding mirrors to a room can have a lightening effect. Paul rushed and picked up the other end of the table, lightening the load for Peter. The Smithsonian. Once lightning hits, the electromagnetic waves travel through two copper coils at right angles, inducing a current. When New York rapper Azealia Banks took to Facebook this month to defend her use of skin-lightening products, she came armed with claims of hypocrisy.
This flying radio could deliver secure communication with greater range and flexibility while lightening the load for troops by reducing the burden of radio carrying.
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ComiXology Thousands of Digital Comics. DPReview Digital Photography. East Dane Designer Men's Fashion.You just touched a metal doorknob after shuffling your rubber-soled feet across the carpet. You've been struck by lightning!
Well, not really, but it's the same idea. Your rubber-soled shoes picked up stray electrons from the carpet. Those electrons built up on your shoes giving them a static charge.
Static means not moving. Static charges are always "looking" for the first opportunity to "escape," or discharge. Your contact with a metal doorknob—or car handle or anything that conducts electricity—presents that opportunity and the excess electrons jump at the chance.
So, do thunderclouds have rubber shoes? Not exactly, but there is a lot of shuffling going on inside the cloud. Lightning begins as static charges in a rain cloud.
Winds inside the cloud are very turbulent. Water droplets in the bottom part of the cloud are caught in the updrafts and lifted to great heights where the much colder atmosphere freezes them.
Meanwhile, downdrafts in the cloud push ice and hail down from the top of the cloud. Where the ice going down meets the water coming up, electrons are stripped off. It's a little more complicated than that, but what results is a cloud with a negatively charged bottom and a positively charged top. These electrical fields become incredibly strong, with the atmosphere acting as an insulator between them in the cloud.
Lightning happens. The electric field "looks" for a doorknob. Sort of. It looks for the closest and easiest path to release its charge. Often lightning occurs between clouds or inside a cloud.Not to be confused with: lightening — becoming lighter or brighter: The sky began lightening as the storm passed.
An abrupt, discontinuous natural electric discharge in the atmosphere. Moving or occurring with remarkable speed or suddenness. Physical Geography a flash of light in the sky, occurring during a thunderstorm and caused by a discharge of electricity, either between clouds or between a cloud and the earth.
See lighten 1-ing 1 ]. A flash of light in the sky caused by an electrical discharge between clouds or between a cloud and the Earth's surface. The flash heats the air and usually causes thunder. Lightning may appear as a jagged streak, a bright sheet, or, in rare cases, a glowing red ball.
Did You Know? The rapid expansion of this superheated air is what creates the sounds we call thunder. The sounds travel to us more slowly than the light from lightning, so it is possible to estimate how far away a lightning strike is by timing the gap between when you see the lightning and when you hear the thunder it has produced. Count the seconds from when you see the flash until you hear the thunder, and divide this number by five.
The result will be the number of miles you are from the point of the strike. See also atmosphere ; clouds ; rain ; thunder ; weather. Switch to new thesaurus. Related words adjectives fulgurousfulminous fear astraphobia. The house was struck by lightning. Mentioned in? References in classic literature? It is not merely courting death or other accident from lightningbut it is bringing the lightning into where he lives.
View in context. And despite the downpour, the deafening thunder and the lightning that seemed ready to sear one's eyes, he walked out of the cave entrance, followed by Tom and the others.Volcanic Lightning - WTF Weather
Close on its apparition, and blindingly violet by contrast, danced out the first lightning of the gathering storm, and the thunder burst like a rocket overhead. The storm had drifted on to the opposite side of the sky, and there were flashes of lightning and distant thunder from that quarter. When darkness came on, sky and sea roared and split with the thunder, and blazed with the lightningthat showed the disabled masts fluttering here and there with the rags which the first fury of the tempest had left for its after sport.
Their business was so important that they decided to push on, despite the darkness and the mutterings of an approaching storm, which eventually broke upon them just as they arrived opposite the "Spook House. I used to lie in my bed by the open window, watching the heat lightning play softly along the horizon, or looking up at the gaunt frame of the windmill against the blue night sky.
The wind began to moan in hollow murmurs, as the sun went down carrying glad day elsewhere; and a train of dull clouds coming up against it, menaced thunder and lightning. Large drops of rain soon began to fall, and, as the storm clouds came sailing onward, others supplied the void they left behind and spread over all the sky. Succeeding years, too wild for song, Then rolled like tropic storms along, Where, through the garish lights that fly Dying along the troubled sky, Lay bare, through vistas thunder-riven, The blackness of the general Heaven, That very blackness yet doth Ring Light on the lightning 's silver wing.
It thundered, and bright flashes of lightning now and again shot across the sky, turning it into a sea of fire.Add lightning to one of your lists below, or create a new one. Heads-ups and wake-up calls! The language of warnings. Definitions Clear explanations of natural written and spoken English. Click on the arrows to change the translation direction.
Follow us. Choose a dictionary. Clear explanations of natural written and spoken English. Word Lists. Choose your language. My word lists. Tell us about this example sentence:. This is a good example of how the word is used. The word in the example sentence does not match the entry word. The sentence contains offensive content. Cancel Submit. Your feedback will be reviewed. B1 a flash of bright light in the sky that is produced by electricity moving between clouds or from clouds to the ground :.
That tree was struck by lightning. Fractals are used in the study of things like forked lightning and to produce some types of computer graphics. The computer failure was due to a glitch caused by lightning. The lightning had damaged the plane's instrumentsand they weren't giving any readings.
Have you ever been struck by lightning? A special system prevents the circuitry being tripped accidentally by a power surge or lightning strike. Precipitation: stormy weather. Idioms lightning never strikes twice. That tree was struck by lightning in a recent thunderstorm.Do not use a corded telephone.
Lightning may strike exterior phone lines. Do not use electric equipment like computers and appliances during a storm. Stay away from windows and doors and stay off porches. Call or send for help immediately. The injured person does not carry an electrical charge, so it is okay to touch them. Lightning is a bright flash of electricity produced by a thunderstorm. All thunderstorms produce lightning and are very dangerous. If you hear the sound of thunder, then you are in danger from lightning.
Lightning kills and injures more people each year than hurricanes or tornadoes; between 75 to people. What causes lightning? Lightning is an electric current. Within a thundercloud way up in the sky, many small bits of ice frozen raindrops bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges.
The positive charges or protons form at the top of the cloud and the negative charges or electrons form at the bottom of the cloud. Since opposites attract, that causes a positive charge to build up on the ground beneath the cloud. The grounds electrical charge concentrates around anything that sticks up, such as mountains, people, or single trees. The charge coming up from these points eventually connects with a charge reaching down from the clouds and - zap - lightning strikes!
Have you ever rubbed your feet across carpet and then touched a metal door handle? If so, then you know that you can get shocked! Lightning works in the same way. Click Here to see where lightning is currently striking across the U. How hot is lightning? Lightning is approximately 54, degrees Fahrenheit. That is six times hotter than the surface of the sun!
What color is lightning? Lightning seems to be clear or a white-yellow color, but it really depends on the background. What causes thunder? Thunder is caused by lightning. When a lightning bolt travels from the cloud to the ground it actually opens up a little hole in the air, called a channel.
Once then light is gone the air collapses back in and creates a sound wave that we hear as thunder.
Lightening vs. Lightning—What’s the Difference?
The reason we see lightning before we hear thunder is because light travels faster than sound! How do you know if lightning is nearby? If you see dark clouds, then lightning could be present, but the best thing you can do is to listen for thunder. If you hear thunder, then you need to go indoors or get in a car. Don't be outside, where lightning could strike!
If your hair stands on end or your skin starts to tingle, lightning maybe about to strike. Get down on your hands and knees and keep your head tucked in.