Phenomenon of lightning

GROUP 6

* KENNETH MARK BALANZA* RAMIELLE BADILES* CRISTOPHER BALAJADIA* CHRISTIAN B. ORDILLOS

Lightning is terrifying, beautiful and confusing phenomenon

Lightning in ancient legends

For many years, people used to believe that lightning

is a holy event which is related to gods that punish

those people who disobey them. People believed that

“Zeus” is the god of lightning ,at that time the smartest

man used to believe in these myths.

Zeus……God of the Lightning!!!!

The first one to study this phenomenon

In the eighteenth century and after eleven centuries,

many scientists started to study the phenomenon of

lightning and the one who made the initiative was

professor “Franklin” who used his famous kite when

he connected it to a metal wire and sent it up between

the clouds, a strong spark was released when the

electricity moved through the wire when it touched the

ground!

Franklin is the first one who proved that the lightning is an electric spark

1752

Simply, lightning is the meeting of negative charges with positive charges

negative charges

positive charges

The knowledge about the lightning was rare till the end of

the twenty century when the scientists discovered the

digital camera as they became able to capture 1000 photo

per second which enabled them to understand some

secrets about the lightning but details still unknown!

A historical fact

The lightning needs special kind of clouds during the thunder storms

The question is: where does the lightning happen ?

Lightning in numbers around the world

• There are 100 lightning strike per second .

• There are 8 million lightning strike every day.

• In America the lightning kills 100 person every year.

A satellite photo

Marvelous numbers!

• Temperature of the lightning beam is 30000 Celsius

so it is five times greater than the temperature on the

surface of sun!!

• The volt per beam is: 1000 million volt.

• Electricity is: 200 thousand ampere

A lightning flash at midnight

The above photo shows lightning flash at midnight , if you exposed to that flash you may became a permanently or

temporally blind according to the distance between you and the flash.

The scientists are studying the lightning….how?

The scientists are choosing a perfect cloud to study ,time

of the lightning flash and the time between each phase as

those scientists believe that the lightning flash differs

from a cloud to another according to how far it is from the

ground, amount of electrical charges in the cloud and on

the ground ,temperature ,wind speed and humidity.

An ideal cloud 3 kilometers far from the ground

How does the lightning occur ?

The lightning occurs in phases

The scientists discovered that the lightning occurs in

two main phases which are the crossing phase and

the returning phase, and they captured photos for

these two phases and said with certainty that the

lightning descends from the cloud and returns again!!

The first phase

A negative charge

descends from the cloud

toward the ground in

part of a second.

The second phase

The positive charge on

the ground meets with

that negative charge.

The third phase

As a result, a strong electric

spark generates and goes

toward the cloud.

The fourth phase

Here we can see the

returned electric charge

and that is the lightning

beam, all of these four

phases happens in 25

Millisecond.

A millisecond is a thousandth (1/1,000) of a second

A simple drawing demonstrates the Mechanism of lightning

~0.001 s ~0.05 s

DartLeader

Streamer

Tracer

1000 km/s100 000 km/s

Returnstroke

Kinds of lightning

Cloud-to-Ground

This is the archetypal lightning bolt -- one that arcs out of the sky and smites the ground with a great, often flickering flash of light. Lightning is the sudden release of built-up charge stored in an electric field, though exactly what

triggers it remains a mystery

Cloud DischargeThis is lightning that occurs within a thundercloud, between 2 thunderclouds, or from a thundercloud to the air. Experts think most cloud discharges take place within an individual cloud, though few data exist to confirm that belief. Cloud discharges are certainly more common than the cloud-to-ground variety: 10-or-more cloud flashes may occur before the

first one that strikes the Earth.

Blue Jet

'Blue Jets' shoot upward from the tops of thunderclouds. This remoteness -- and the fact that they last but a few hundred milliseconds at most -- perhaps accounts for why they were not discovered until 1994. They are the color of sapphires, are cone-shaped in structure, and extend for

many miles .

Red Sprites

'Red Sprites' occur above large thunderstorm systems and are generally associated with larger positive cloud-to-ground flashes far below. They are most luminous very high up in the atmosphere between altitudes of about 25 and 55

miles .

Elves

Like celestial halos, elves are circles of light that appear some 50 miles-or-more above thunderstorms. Triggered by lightning flashes far below, these ephemeral discs spread out radially across the bottom of the ionosphere in the briefest instant, expanding up to hundreds-of-miles in

diameter in less than a millisecond .

Volcanic Lightning

Lightning-like discharges are sometimes observed during volcanic eruptions with no thunderstorm anywhere nearby. Hundreds or even thousands of feet in length, these bolts can flash to the ground or remain entirely within the ash cloud above the

volcano .

Nuclear Lightning

Hydrogen-bomb explosions can generate their own lightning. Ground-level detonations -- like this 1952 test of an experimental thermonuclear device on Eniwetok in the South Pacific -- cause a negative charge to be deposited in the atmosphere, resulting in long discharges

not produced by clouds .

Triggered Lightning

"Triggering lightning at will -- at a predetermined place and time -- is the old Promethean dream which seems more related to legend than to Science," lightning expert Pierre Hubert has written. Yet the technique has taught scientists much about lightning processes and

effects .

THANK YOU!