Wednesday August 15, 2018
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# Explained: Physics related to everyday life

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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

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# Scientists Think Microbes May be the Reason Behind Tunnels in Thai Garnets

The researchers argue that the microbes bored into the garnets while they were in the river bed. Microbes in the sediment of the river lack access to chemical energy sources like iron, which is contained in the garnet crystals.

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Life has found a way to survive in some of the most extreme conditions imaginable. Now, scientists believe they might have found a new habitat for hardy microbes — inside garnets.

New research found unusual patterns of tunnels in Thai garnets with deposits of fatty acids in the burrowed pathways, indicating a microbe caused the damage.

Magnus Ivarsson, lead researcher on the study at the University of Southern Denmark, said the research started with an exchange student from Thailand who was studying the gem quality of the garnets. She discovered the tunnels that branched and changed directions, unlike previously described environmental weathering, and consulted Ivarsson.

“When I first saw these structures, these tunnels, I was sort of intrigued by the complexity of them,” Ivarsson told VOA. “I have previously studied other microbial boring in minerals and materials, but I’ve never seen anything with this complexity.”

The garnets are an unexpected habitat for microbes because of their hardness. In fact, according to Ivarsson, this is the hardest mineral yet discovered to be bored by microbes.

“Who knows what we’ll find next. Maybe a diamond bored by microbes. Who knows?” Ivarsson said.

Researchers are careful to point out that no living organisms were discovered within the gemstones.

Dawn Cardace, a researcher in the department of geosciences at the University of Rhode Island, studies how geology and biology interact. She told VOA that while this study didn’t find any DNA of the organisms, “This wasn’t troubling to me, largely because they chose to work with the sample set they have at a very close, submicroscopic scale.” She said they would have needed at least a thousand gemstones in order to collect a DNA sample.

The researchers relied on several technologies to come to their conclusions.

First, the scientists used microscopy to make 3D maps of the tunnels on the scale of microns. A human hair is about 50 microns wide, but the tunnels in the garnets were generally smaller, hence the need for high-powered microscopes.

The scientists focused on how the tunnels spread and changed directions, and when they converged at crossing points called “anastomosis.” Although environmental weathering can cause cracks and fissures in hard minerals, Ivarsson said weathering processes can’t explain the complexity of the tunnels they observed.

The second step to demonstrate that microbes most likely created the tunnels required analyzing the interior of the boreholes.

“The organic content tells us that there’s been life living in there,” said Ivarsson.

In particular, they detected lipids and fatty acids, which are organic compounds common among bacteria and fungi.

Ivarsson and his colleagues compared these biological traces to hematite and quartz grains found in the same location as the garnets, in the river sediment of the Chiang Mai stream. Neither of the comparable stones showed signs of fatty acids, indicating the biological traces were unique to the garnet tunnels.

When asked about the results, Ivarsson said, “At this point we can say at least that biology has been involved. I would suggest that it’s fungi that has been involved in this. But at the same time, I think we should be really cautious because there might be other processes [at work] that are not known today.”

More studies needed

Cardace agrees that while microbes were certainly living inside the gemstones, further research is needed to prove how the tunnels were created. She said she would like future studies to show “a set of experiments done with candidate microorganisms that could do the metabolic work” the researchers proposed in their paper.

Ivarsson and his colleagues did, however, consider why microbes like fungi might be making the garnets their home. They sampled garnets from river sediment in Thailand, as well as within granite upstream.

Ivarsson told VOA, “When we studied these garnets in the granite, we could see that there were no tunnels. But when we looked at the garnets further down the river, we could see that these tunnels structures had evolved. So, something happened along the way, along the transport in the river system.”

The researchers argue that the microbes bored into the garnets while they were in the river bed. Microbes in the sediment of the river lack access to chemical energy sources like iron, which is contained in the garnet crystals. Perhaps, researchers propose, the microorganisms created the filaments within the gemstones to access this resource.

Monetary value

Such changes to the garnets, however, decrease the value of the stones.

Shane McClure, global director of colored stones at the Gemological Institute of America, told VOA that when it comes to determining the value of garnets, “If there’s only one or two [tunnels] and they’re very small, it doesn’t affect the value at all. But if there’s a whole bunch of them and they’re very visible, well then it’s going to affect it quite a bit from a gemstone perspective.”

These gemstones might not be usable for flashy jewelry, but they do demonstrate that life finds a way in all sorts of inhospitable and unexpected locations.

Also Read: Jewellery Trends For 2018

As Ivarsson told VOA, “When we look for life on Mars, we need to know what to look for. And this is one type of biological signature that is definitely interesting in the search for life on Mars or any type of extreme environment.” (VOA)