Lightning: Nature’s Electric Display and Safety Measures

Lightning is a natural atmospheric discharge of electricity that occurs during thunderstorms. While captivating, it poses safety risks, and its study helps in understanding atmospheric phenomena and implementing measures to protect lives and property from the associated hazards.

Understand Lightning: 

• Meaning: It is an electric spark caused by charge imbalance between clouds and the ground, due to accumulation of charge in the cloud.
  • In ancient times, people feared it, thinking it was the wrath of gods.

Lightning: Historical Insights and Scientific Milestones

• Discovery: In 600 BC, the Greeks discovered the phenomenon of static electricity, noticing that amber, when rubbed with fur, attracted light objects due to electric charges.
• Realization: In 1752, Benjamin Franklin scientifically proved the correlation between lightning and sparks from clothing, a realization that took the world 2000 years to acknowledge.

Static Electricity: Charging and Electron Transfer in Lightning

• Static Electricity: When objects are rubbed together, the movement of electrons occurs, resulting in the positive charging of one object and the negative charging of the other, a fundamental phenomenon in static electricity.
• Transfer of Charges: The rubbing of a plastic refill with polythene results in charge transfer, leading to the formation of charged objects.
  • Examples: This phenomenon can be observed in various materials, including balloons, erasers, and steel spoons.
• Electric charges produced by rubbing remain static until they are set in motion, forming an electric current.

Electric Charges and Their Interaction in Lightning

• Movement of Electrons: During the rubbing process, electrons move from one object to another, causing an excess of electrons in one and a deficiency in the other, resulting in the creation of charged objects.
  • Example: When a glass rod is rubbed with silk cloth, the glass becomes positively charged, and the silk cloth becomes negatively charged, showcasing the transfer of electric charges between them.
• Negatively Charged: Objects having an excess of electrons are called negatively charged.
• Positively Charged: Objects having a shortage of electrons are called positively charged.
• Electric Current: The electrical charges generated by rubbing are static. They do not move by themselves. When charges move, they constitute an electric current.
• The current in a circuit which makes a bulb glow, or the current that makes a wire hot, is nothing but a motion of charges. 
• Like charges repel each other. Unlike charges attract each other.

Earthing in Lightning Protection

• When we touch charged aluminum foil, charges flow through our bodies since humans are good conductors, grounding the charges to the earth.
• Earthing: The process of transferring charges from a charged object to the earth is called earthing.
  • Earthing is provided in buildings to protect us from electrical shocks due to any leakage of electrical current.

Occurrence of Lightning

• In rain or thunderstorms, air rises while water droplets fall.
• During rain, charges segregate, positive charges accumulate near the upper edges of clouds, and negative charges accumulate near the lower edges.
• Additionally, positive charges accumulate on the ground.
• Between the clouds and the ground, the air is present which typically exhibits poor conductivity for charges.
  • However, when its resistance diminishes, it begins to conduct charges.
• Negative and positive charges collide, resulting in bright light and sound, visible to us as lightning, known as electric discharge.
• Electric discharge can happen between clouds and the earth’s surface or between two clouds in the atmosphere. 

Lightning Safety Guidelines to Follow

Outdoors:

• Seek refuge in a secure location, like a small grove of trees.
• If you are inside a vehicle, remain inside with closed doors and windows.
• Keep a safe distance from metal poles.
• Avoid lying on the ground; instead, crouch down with your head protected by your hands.

Indoors:

• Refrain from touching telephone and electrical wires.
• Avoid taking a bath during a thunderstorm.
• Unplug electrical appliances as a precautionary measure.

Lightning Conductors

• This conductor is a device used to protect buildings from lightning.
• In the construction phase, a metallic rod is meticulously placed along the building’s upper edge. 
• One end extends into the air, creating a lightning-attracting point, while the other end is firmly grounded below the surface, ensuring a secure path for the discharge.
• When a thunderstorm strikes the rod, charges transfer to the earth, leaving the building unharmed and protected.