Some Natural Phenomenon Flashcards
What is lightning?
The process of electric discharge between clouds and the earth or between different clouds or accumulation of charges in the clouds causes lightning. Lightning strike could destroy life and property.
Name some examples in which electric discharge is seen?
When amber is rubbed with fur, it attracts light objects such as hair. When we take off wool or polyester clothes our hair stands at the end, and if we take them off in the dark we can even hear a crackling sound and sparks.
Who proved that lightning and the other examples are from the same phenomena ?
In 1752, Benjamin Franklin, an American scientist showed that lightning and the spark from your clothes are essentially the same phenomena.
What is an electric discharge?
When negative charges from the clouds and positive charges on the ground meet, a huge amount of energy is produced as bright light and sound, which we see as lightning. The process is called electric discharge.
Describe the types of charges.
There are two types of charges-positive charge and negative charge.
Positive - When the charge of an object is due to the loss of electrons, it is called a positive charge.
Negetive - When the charge of an object is due to the excess of electrons, it is called a negative charge.
° When we rub two objects, made of different substances, together the charge they acquire are opposite to each other.
What are the characteristics of charges?
The opposite charges always attract and the same charges always repel each other.
The charges generated by rubbing are called static. They don’t move by themselves when charges move they are constituting and electric current.
What is the convention of charge?
It is a convention to call the charge acquired by a glass rod when it is rubbed with silk as positive and the silk would get negative charge.
What is an electroscope? how can we make it and which Idea does it promote?
Electroscope is a device used to test whether an object is carrying charge or not.
An electroscope consists of a large jar. A metal rod is fitted into the mouth of the jar with the help of the cork. At the lower end of the metal rod, a pair of thin leaves of gold or aluminium is suspended. If the object in contact with the metal rod is charged then gold leaves repel and if it is not then they would be at rest.
It transports an idea that Electrical charge can be transferred from a charged object to another through a metal conductor.
What is discharge and what is earthing?
An object when loses its charge is said to be discharged and the process of transferring of charge from a charged object to the earth is called earthing.
How does lightning occur?
During a thunderstorm, the air currents move upward, while the water droplets move download, these vigorous movements cause separation of charges and positive charges collect near the upper edges of the cloud and the negative charges accumulate near the lower edges. There is an accumulation of positive charges near the ground also, when the magnitude of the accumulated charges become very large, the air which is normally of poor conductor of electricity is no longer able to resist the flow producing streaks of light and sound called as lightning.
How can we protect ourselves from lightning?
OUTSIDE
- During lightning and thunderstorm no open place is safe. The house are building is the safe place. If you are travelling in a car or a bus you are safe inside with windows and those of the vehicle shut.
- Hearing thunder is an alert to rush to a safer place.
- We shouldn’t carry umbrellas as it contain a metal above it which will attract lightning to strike.
- we should be in the lowest area possible which is a squat.
- After hearing the last thunder, wait
for some time before coming out of the safe place.
- if in a forest take shelter under shorter trees.
- If there is no shelter then be far away from all the trees, poles or metal objects.
INSIDE
-Lightning can strike telephone cords, electrical wires and metal pipes, during a thunderstorm contact with these should be avoided.
-Bathing should be avoided during thunderstorm to avoid contact with running water.
-Appliances like computer, TV’S, etc should be unplugged, electrical lights can remain on they do not cause any harm.
What is lightning conductor and what does it do?
Lightning conductor is a device used to protect building from the effect of lightning, it is a metallic rod taller than the building and is installed in the walls of the building during its construction. One end of the rod is kept out in the air and the other is buried very deep in the ground. It promotes the idea of earthing.
What are earthquakes?
An earthquake is a sudden shaking or trembling of the earth which lasts for a very short of time. It cause large scale destruction of human life and property. They are caused by the disturbance deep inside the earth’s crust. Earthquakes can also cause floods, landslides and tsunamis.
* A major tsunami occurred in the Indian Ocean on 26 December 2004.
Name two major earthquakes that occurred in India.
- A major earthquake occurred in India on 8 October 2005 in Uri and Tangdhar towns of North Kashmir.
- A major earthquake occurred on 26 January 2001 in Bhuj district of Gujarat.
# Both these earthquakes were above the magnitude of 7.5.
How are earthquakes formed? What is Focus and epicenter?
Earthquakes are formed by the tremors caused by the disturbances deep down inside the earth. The upper most layer of the earth called The crust. The outermost layer ( crust ) of the Earth is not in one piece, it is fragmented into several parts called plates, these plates are in continual motion. When they brush pass on one another or a plate goes under another due to collision, they cause earthquakes.
Focus is the point inside the earth where the earthquake originated and epicenter is the point just above the focus but on the earth’s surface. The epicenter bears the most damage.
