Page 1 - lesson notes- Lightning

SAI INTERNTIONAL SCHOOL
Class 8
Lesson notes
Subject- Physics
Ch- Some Natural Phenomena
Subtopic- Lightning

LIGHTNING: The bright flash of light which we see in the clouds as a result of
electric discharge is called lightning.
• The electric discharge in the atmosphere is either between the clouds
or between the earth and the ground.
• There are two types of lightning: 1) Sheet lightning 2) Fork lightning
• Sheet lightning: It is between the clouds having opposite charge.
• Fork lightning: It is between the clouds and the ground.
Lightning Conductor: It is the device installed on the buildings to protect it
from lightning.
• Construction: It is a metallic rod installed at the top of building during
the construction. The rod is attached to a copper strip whose other end
is buried under the ground.
• Working: When lightning strikes a building, it first strikes the metal rod
and will be conducted to the ground through the metal strip. This way
buildings remains safe from the lightning.

Protection from lightning:
• Indoor:
o We should not use electrical appliance during lightning. They
should be unplugged.
o Avoid contact with the wired telephones.