1) Static charge
Static charge is the electric energy developed when two objects rub against each other and then break contact. Unlike current electricity, static electricity doesn’t flow through the object. The charge sits at one spot and discharges itself when it comes in contact with a body with the opposite charge. This discharge creates the slight shock we sometimes experience when touching charged objects. Static charge is a part of several of our daily activities, and thus learning about it is useful.
2) Charged objects
Why does friction between two objects create a static charge? When objects simply sit in close contact, they do not produce a static charge. When objects rub against each other, the movement creates a flow of energy. Loosely bound electrons move from object A to object B. In object A, the number of electrons grows less than the number of protons; this creates a positive charge on A. In object B, the number of electrons grows more than the number of electrons; this creates a negative charge on B. The positive charge on A is equal to the negative charge on B. Together, A and B balance these charges and remain neutral. But individually they are in an imbalance with each other and other objects.
3) Interaction between charged objects
Similar charges repel each other, while opposite charges attract each other.
When you remove a hat after wearing it for a while, the friction between your hair and the hat creates a static imbalance. The hat becomes positively charged, while your hair becomes negatively charged because of transferring electrons. As a result, your hair stands up and away from each other. All your hair possesses the same negative charge, thus, they repel each other. They move in the hat's direction because its positive charge attracts the negatively charged hair.
Why do we sometimes feel a shock when we touch a metal object?
Static interaction does not happen between any and every object. It occurs when one of the interacting objects is a non-conductor of electricity, a.k.a. insulator, and the other is a conductor.
Object A rubs against object B and loses electrons to it. But B is an insulator; it only collects electrons and does not return them to A. Thus, B gets negatively charged and A gets positively charged. A will not receive a static shock when interacting with another insulator B2, since there will be no flow of electrons.
But when A comes in contact with a conductor C, whose electrons readily flow across towards the positively charged A, A will receive a static shock. We see it as a bright blue-white spark.
The static spark is a noteworthy feature, as it creates a problem by causing inflammable material to catch fire. For example, airlines take special care to neutralise all charges while refuelling an aeroplane.
A static spark can even damage electronic devices. That’s why they come encased in an anti-static cover.
4) Lightning
Lightning is one of the most prominent and powerful displays of static electricity. Air and water particles collide with each other inside the cloud. This causes the top half of the cloud to become positively charged, while the bottom half is negatively charged. When the charges grow strong, lightning occurs.
Most lightning occurs inside and between the clouds. However, since the ground is positively charged, it also attracts lightning from the negatively charged cloud. Electrons from the ground travel across conducting objects, while electrons from the cloud extend towards positively charged hotspots on the Earth. These two streams meet and cause lightning.
This process happens faster than humans can perceive.
Lightning used to be a frightening mystery for early humans. But over the years, people used scientific methods to demystify the phenomenon, learn more about it, and safeguard themselves.
5) Earthquake
From the centre to its surface, Earth has multiple phases of matter. The outermost layer, called Lithosphere, is solid. Meanwhile, the Outer Core, the layer under the lithosphere, is semi-liquid. The lithosphere is like a puzzle board, divided into multiple pieces called tectonic plates. These pieces move continuously. The friction caused when they rub against each other generates stress, which gets stored in the solid rock. This stress travels up to the surface and creates a wave called a seismic wave. This wave shakes and displaces the surface of the Earth, causing an earthquake.
Earthquakes vary in intensity; while some are barely felt, others may cause mass destruction. Though we know what an earthquake is and how it happens, we have not yet developed a mechanism that will allow us to predict its arrival. However, we have been able to measure their intensity.
This shows how we need to keep learning about nature and its puzzling phenomena.
Maths (16)