Thursday October 18, 2018
Home India Explained: Ph...

Explained: Physics related to everyday life

0
//
489
Image-epi.edu.com
Republish
Reprint

By Aakash Sinha

When I was a child, many unusual questions used to trigger my mind, some I got the answers and rest are still unexplored. Human is a social animal with brains. We have got a special ability, we can reason. In our day-to-day life, we come across several stuff which we accept it without knowing the cause of that activity. But the question is why? How?

In this article, we will see the reason behind some of the activities that we see every day but never questioned about it.

Why the wheels of any vehicle are circular?

  • Quite interesting! I noticed it when I was 12 years old. Well, everyone uses a cycle, bike or a car, watching the wheels every day. But, why can’t the wheels be rectangular or square? Why circular? There is the force that opposes every force called friction force. We can walk, run & stop; all due to this force. Wheels of the automobiles are made circular to reduce the frictional force. On a circular body, rolling friction acts which is less than the sliding friction (a type of friction that acts on all bodies other than circular) which is responsible for the wheels to be circular. If wheels would have some other shape, sliding friction would come into picture increasing the resistance in movement of automobiles.

Why tube light blinks before turning ON?

  • Every day we come across this phenomenon but the reason remains unnoticed. A tube light has a low-pressure mercury vapour with a phosphorous coating, white in colour which we can see from our eyes. When the tube light is turned ON, it flickers. That flicker is caused because the gas inside the lamp is relatively cold and cannot establish glow discharge between the two electrodes. Once the heat is developed, gas ionizes and gives out the ultraviolet light enabling the phosphorous coating to glow.

Why the moon looks bright yellow at night?

  • Moon is connected to humans involving different emotions and expressions. Moon does not have its own light. It is just an illusion. Then, how does it shine? That bright colour of the moon is due to the reflected light from Sun which bounces off the dark grey and bumpy surface of the celestial body, falling on our eyes. The shocking fact is that only 3% to 12% of light is reflected from the surface of the moon but still the brightness is more than a star. We can see the moon during day time but we can’t see the stars.

Why do stars twinkle at night?   

  • Twinkle- Twinkle little star….. The poem taught to every child always tickled my mind when I was 16. Our Earth atmosphere is very turbulent and made up of different layers of air moving in all directions at different intensities. Light from the stars travel a very long distance before falling on our eyes. When it passes through the atmosphere, it bends due to refraction which makes it appear to twinkle. The Scientific name of the twinkling of stars is ‘astronomical scintillation’. Thank God! The poem was not written by a scientist.

Why the sky is blue in colour?

  • The rays of the sun are made of 7 colours (Violet, Indigo, Blue, Green, Yellow, Orange, and Red). As the white light passes through Earth’s atmosphere, it collides with particles of air. The different colours or wavelengths of light are scattered by this collision by different amounts. Blue light (shorter wavelength) is scattered more than red light (longer wavelength).When sun is high in the sky, blue light is scattered in all directions and sky appears blue.

How water comes inside the coconut?

  • Clusters of coconut palms thrive on seashore outside the tidal zone provided there should be a plenty of subterranean fresh water. As the fresh water accumulated by the roots is conveyed right up to the crowns of the coconut palms through osmosis process, any dissolved salts which exist in that water is eliminated through natural filtration. The water inside the coconut is actually ‘endosperm’ or the food or the nourishment for the coconut’s growth. As the coconut ripens the water becomes less pleasant to drink.

How does water come on Earth?

  • After the big bang almost 13.8 billion years ago, the energy that sparkled in the Milky Way galaxy lead to the formation of Earth. That time Earth was boiling at a very high temperature. The water we have today came into existence much after the formation of the blue planet (Earth). Comets and asteroids can contain ice. The collision of wet comets and asteroids is responsible for the existence of life-giving liquid, “water” on Earth. The study shows that meteorites from Vesta (a group of meteors near to Jupiter) have the same chemical makeups (rocks) as that of our Earth. The mystery is not yet solved, but suspects’ asteroids.

How a program recorded in a studio reaches our Television sets?

  • We enjoy watching different programs on T.V but we never think of the engineering behind the telecasting of any program. There are three divisions of a Television station:-
  • Studio
  • Earth Station
  • Transmitter

A studio is the action area of artists where they perform any act. When the program is recorded it is sent to the Earth Station via cables. Earth station is a terrestrial terminal station designed to uplink and downlink data (programs) to and fro from the satellite. Once the program is uplinked to the satellite it can be viewed in any part of the country using the transmitter and receiver unit (at home, DTH). The program is downlinked at a T.V tower unit, then the different frequency is embedded for different programs (for DD News= 224.5MHz) in the form of electromagnetic waves. These waves are then transmitted in the air through an antenna. Now the same frequency is identified by the T.V receiver, it decodes it and we can see the desired program.

Have you ever noticed the direction of your DTH antenna? 

  • Once I was standing on the terrace, I observed that all the antenna of DTH is pointing towards the same direction. I was amazed. That dish antenna points towards the satellite of the country from where it can receive the signals (Radio frequency). In India, every dish antenna points towards South-East.

We cannot solve the problems with the same thinking we used when we created them – ALBERT EINSTEIN

Aakash is a student of engineering at Sir M. Visvesvaraya Institute of Technology, Bangalore. Twitter @aakashsinha1994

Click here for reuse options!
Copyright 2016 NewsGram

Next Story

Invasive Species May Not Be All Bad: Scientists

An active debate among biologists about the role of invasive species in a changing world is going on

0
Invasive Species
The invasive European green crab is tearing down ecosystems in Newfoundland and building them up on Cape Cod. VOA

Off the shores of Newfoundland, Canada, an ecosystem is unraveling at the hands (or pincers) of an invasive crab.

Some 1,500 kilometers (930 miles) to the south, the same invasive crab — the European green crab — is helping New England marshes rebuild.

Both cases are featured in a new study that shows how the impacts of these alien invaders are not always straightforward.

Around the world, invasive species are a major threat to many coastal ecosystems and the benefits they provide, from food to clean water. Attitudes among scientists are evolving, however, as more research demonstrates that they occasionally carry a hidden upside.

“It’s complicated,” said Christina Simkanin, a biologist at the Smithsonian Environmental Research Center, “which isn’t a super-satisfying answer if you want a direct, should we keep it or should we not? But it’s the reality.”

Simkanin co-authored a new study showing that on the whole, coastal ecosystems store more carbon when they are overrun by invasive species.

Good news, crab news

Take the contradictory case of the European green crab. These invaders were first spotted in Newfoundland in 2007. Since then, they have devastated eelgrass habitats, digging up native vegetation as they burrow for shelter or dig for prey. Eelgrass is down 50 percent in places the crabs have moved into. Some sites have suffered total collapse.

That’s been devastating for fish that spend their juvenile days among the seagrass. Where the invasive crabs have moved in, the total weight of fish is down tenfold.

The loss of eelgrass also means these underwater meadows soak up less planet-warming carbon dioxide from the atmosphere.

In Cape Cod, Massachusetts, the same crab is having the opposite impact.

Off the coast of New England, fishermen have caught too many striped bass and blue crabs. These species used to keep native crab populations in check. Without predators to hold them back, native crabs are devouring the marshes.

But the invasive European green crab pushes native crabs out of their burrows. Under pressure from the invader, native crabs are eating less marsh grass. Marshes are recovering, and their carbon storage capacity is growing with them.

Invasive species
In this May 8, 2016 photo, eelgrass grows in sediment at Lowell’s Cove in Harpswell, Maine. VOA

Carbon repositories

Simkanin and colleagues compiled these studies and more than 100 others to see whether the net impact on carbon storage has been positive or negative.

They found that the ones overtaken by invasive species held about 40 percent more carbon than intact habitats.

They were taken by surprise, she said, because “non-native species are thought of as being negative so often. And they do have detrimental impacts. But in this case, they seem to be storing carbon quicker.”

At the Smithsonian Environmental Research Center where she works, the invasive reed Phragmites has been steadily overtaking a marsh scientists are studying.

Phragmites grows much taller, denser and with deeper roots than the native marsh grass it overruns.

But those same traits that make it a powerful invader also mean it stores more carbon than native species.

“Phragmites has been referred to as a Jekyll and Hyde species,” she said.

Not all invaded ecosystems stored more carbon. Invaded seagrass habitats generally lost carbon, and mangroves were basically unchanged. But on balance, gains from marsh invaders outweighed the others.

Invasive species
Phragmites plants growing on Staten Island draft in a breeze in the Oakwood Beach neighborhood of Staten Island. VOA

Not a lot of generalities

To be clear, Simkanin said the study is not suggesting it’s always better to let the invaders take over; but, it reflects an active debate among biologists about the role of invasive species in a changing world.

“One of the difficult things in the field of invasion biology is, there aren’t a lot of generalities,” said Brown University conservation biologist Dov Sax, who was not involved with the research. “There’s a lot of nuance.”

The prevailing view among biologists is that non-native species should be presumed to be destructive unless proven otherwise.

When 19 biologists wrote an article in 2011 challenging that view, titled, “Don’t judge species on their origins,” it drew a forceful rebuke from 141 other experts.

Sax said the argument is likely to become more complicated in the future.

Also Read: Climate Change Not A Hoax: Trump

“In a changing world, with a rapidly changing climate, we do expect there to be lots of cases where natives will no longer be as successful in a region. And some of the non-natives might actually step in and play some of those ecosystem services roles that we might want,” he said.

“In that context, what do we do? I definitely don’t have all the answers.” (VOA)