Lightning Discharge 302i2j

Lightning Discharge : This Project is contributed by •Abdallah Ali Hamdan •[email protected] •Ali Nasser Ammar •Rasheed Mohammed EL-Ghorabee •Yousef awidat

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•[email protected]

Lightning Discharge

Project Outline • • • • • • •

Introduction Mechanism Of Lightning Types of strikes & Types Of Lightning Effects Of Lightning Lightning Safety Conclusion References

Introduction • “A lightning strike can heat the air in a fraction of a second. When air is heated that quickly, it expands violently and then contracts, like an explosion that happens in the blink of an eye”. [Steve Goodman, A Lightning Primer,

www.nasa.gov]

• 100 lightning strikes per second . • 8 million lightning strikes per day . • 30000 Celsius is the temperature per strikes . • 1000 million volt per strike. • 20000 ampere per strike.

Mechanism of Lightning • It is the movement of electrons down from a region of more negative charge to a region of less negative charge. • Lightning results from the buildup and discharge of electrical energy between positively and negatively charged areas. • Rising and descending air within a thunderstorm separates these positive and negative charges.

Lightning Mechanism First stage

A negatively charged ray of electrical light falls down from the cloud to the ground in a very little time )about ms(

Lightning Mechanism Second stage

This ray approaches the ground in which it meet with the positively charged wave that is found at the top of the ground

Lightning Mechanism Third stage

The positively charged ray strikes the negatively charged wave and then an extreme spark of light is produced, towards .the ground

Lightning Mechanism fourth stage

Finally the returned ray that we see is produced, and it contains the energy of lightning and its heat, this happens in .))25ms

Lightning Animation

Types of Strikes 1-Cloud to ground. 2-Ground to cloud. 3-Cloud to cloud.

Types of Strikes : Cloud to ground

Types of Strikes

• Ground to cloud: The same as above with the exception that usually a tall, earth-bound object initiates the strike to the cloud

Types of Strikes

• Cloud to cloud : Also the same mechanics as discussed above except the strike travels from one cloud to another

lightning Effect

lightning Effect

lightning Effect

lightning Effect

lightning Effect

Lightning Benefits • What’s good about lightning? • It produces a lot of the nitrogen compounds that are important for plant growth. It provided early man with his only source of fire. It’s better than fireworks on the Fourth of July and it’s free !

Lightning Damage • There are four basic types of lightning damage: 1-physical damage 2-electromagnetic effect damage

Physical damage The Physical damage is caused by current flow and heat.

The average lightning strike contains

20,000 amps. • This current flow can arc across any gaps in its path. If that arc takes place within a flammable material, it can cause a fire or explosion

Physical damage The core temperature of a lightning channel is approximately 50,000 degrees Fahrenheit, or about five times the surface temperature of the sun.

When the air surrounding the lightning channel is heated this rapidly, it expands in a shock wave. This shock wave can damage a structure

Physical damage

The electromagnetic field effect The on-off-on-off action of a lightning strike

causes the electromagnetic field surrounding the strike to expand and collapse with the series of flashes.

 This electromagnetic field motion can induce electrical currents in nearby conductors, including wires and electrical equipment.

Lightning Safety • 30/30 Lightning Safety Rule: -Go indoors if, after seeing lightning , you cannot count to 30 before hearing thunder. Stay indoors for 30 minutes after hearing the last clap of thunder.

Lightning Safety • What is the safest place? • Most people think that the tree was the safe place • •

to be in storm , But really is the most dangerous place. Electricity seeks the path of least resistance, and the moisture )sap and water( inside a tree is a much better conductor than air. The result: a tree provides a preferred path for lightning to reach ground.

Lightning Safety • Can the car safe us from Thunderstorm? • A car is very safe from the storm . • If you are inside a car when lightning strikes , the metal frame will conduct the electricity into the ground ,just do not touch anything metal or radio.

Safety

Safety

Safety

References