Õhus on äikest ja elektrit

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Käsmu 2006

Õhus on äikest ja elektrit

ehk tuli meie lähitaevas

Hannes.Tammet@ut.ee

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HOIATUS

Mõõtmise tulemuseks on arvud. Kui

räägime arvudest, siis räägime millestki, mida ei ole looduses olemas.

Mõttelisi mudeleid võib ehitada nagu meeldib. Mudel pole ei õige ega väär, mudel võib olla vaid enam kasulik või vähem kasulik.

Näide: laev sõidab seisvas vees

kiirusega 20 km/h ja vesi voolab kanalis sõidusuunas 10 km/h. Kui suur on laeva kiirus kanali seinte suhtes?

Mudel 1:

Mudel 2:

2 2 1

2 3 1

1 c v v

v v v



 

2 1

3

v v

v  

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VÄLK ^arvudes

Pinge kuni 1 GV (aga 3 km ja 30 kV/cm?)

võrdlus: kõrgepingeliin 300 kV,

National Electrostatic Corporation'i Pelletron-kiirendi 30 MV.

Voolutugevus 20–100 kA

võrdlus: Elektripliit tarbib ca 10 A. 5000 elektripliiti tarbivad 50 kA.

Võimsus ≈> 1000 GW, töö ≈ 1000 kWh

võrdlus: Kolme Kuristiku Tamm: 18.2 GW,

HERCULES-laser 40 000 GW (3×10

^-14

s)

Eestis tuleb keskmiselt 1 välk aastas ühele ruutkilomeetrile ehk ühel hektaril peab välku ootama sada aastat.

Temperatuur ≈ 30000 K

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MÜRISTAB

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26. august, Holland 1999

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26. august, Arizona 2000

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Paha välk Mõni jääb ellu:

Memory Deficits & Loss 52%

Attention Deficits 41%

Sleep Disturbance 44%

Numbness/Parathesias 36% Dizziness 38%

Easily Fatigued 37%

Stiffness in Joints 35%

Irritability/Temper Loss 34%

Photophobia 34%

Weakness 34% Muscle Spasms 34%

Chronic Fatigue 32%

Hearing Loss 25%

Depression 32%

Inability to Sit Long 32%

External Burns 32%

Severe Headaches 32%

Fear of Crowds 29%

Storm Phobia 29%

Inability to Cope 29%

General Weakness 29%

Unable to Work 29%

Reduced Libido 26%

Confusion 25%

Coordination Problems 28%

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From WIKIPEDIA:

Roy Cleveland Sullivan (1912 – September 28, 1983) was a U.S. forest

ranger in Shenandoah National Park in Virginia. Sullivan was hit by lightning on seven different occasions and survived all of them. In his lifetime he

gained "Human Lightning Rod" as a nickname.

1942: Sullivan was hit for the first time when he was in a fire lookout tower. The lightning bolt struck him in a leg and he lost a nail on his big toe.

1969: The second bolt hit him in his truck when he was driving on a mountain road. It knocked him unconscious and burned his eyebrows.

1970: The third strike burned his left shoulder while in his front yard.

1972: The next hit happened in a ranger station. The strike set his hair on fire.

After that, he began to carry a pitcher of water with him.

August 7, 1973: A lightning bolt hit Sullivan on the head, blasted him out of his car, and again set his hair on fire.

June 5, 1974: Sullivan was struck by the sixth bolt in a campground, injuring his ankle.

June 25, 1977: The seventh and final lightning bolt hit him when he was fishing.

Sullivan was hospitalized for burns in his chest and stomach.

Roy Sullivan shot himself on September 28, 1983.

Two of his ranger hats are on display at two Guinness World Exhibit Halls in New York City and South Carolina.

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Hea välk

?

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Piksekaitse

Maandustakistus on 30 oomi ja voolutugevus 100 kA, leida pinge.

100 mm

²

vaskjuhe soojeneb tugeva välgulöögi tulemusena ca 1 K võrra. Leida juhtme

ristlõige, kui lubada soojenemist kuni 400 K?

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Kuhu välk lööb?

Empire State Building:

100 välku aastas

3. juuni 1902. a.

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1750 1753

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KUNSTVÄLK

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Salapärased

nähtused

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Kuidas tekib elekter pilves?

+

- - - - - - - + + +

+ +

+

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+ + + + + + + + + + + + + + + + + + + + + + +

- - - - - -- -

+ + +

+ +

⁺

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Välk viib negatiivse laengu maha.

Mis saab järele jäänud positiivsest laengust?

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VAHETAEVAS

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Õhus on äikest ja elektrit