Category Science

What is stubble burning?

The air quality in Delhi and other parts of north India hit a hazardous level this month. Levels of dangerous particles in the air – known as PM2.5 – were over 10 times the safe limits in the capital. The air quality index (AQI) crossed an all-time high of 1,000 in some places on November 3. As per data, the AQI between 0 and 50 is considered safe, 51-100 satisfactory, 101-200 moderate, 201-300 poor. At 301-400 it’ considered very poor and 401-500 falls in the severe category. When the AQI crosses the 500 mark, it falls into the emergency category.

The odd-even rule, a car rationing scheme, came into effect on November 4. (As per rule, cars with odd numbers will be allowed to run on odd days such as Nov 5, 7 etc., and cars with even numbers will be allowed on even days such as Nov 6, 8, etc.). Delhi Chief Minister Arvind Kejriwal blamed crop burning in Haryana and Punjab for increased pollution levels in the capital during winter.

Air pollution is a year-round problem in Delhi due to vehicular and industrial emission, but the impact is felt more during the winter months. The capital’s low air quality during the winter is attributed to its geography, low wind speed and stubble burning by farmers in the neighbouring States of Punjab and Haryana. These farmers have come under fire for taking the air quality to a dangerous level.

Stubble burning is the practice of removing crop residue from fields post-harvest by setting fire to it. This usually happens during October and November (autumn months), as the farmers begin to prepare the field for sowing winter crops – especially wheat.

As the southwest monsoon retreats, it sets off northwesterly winds, which carry the smoke from the burning of stubble towards Delhi and other northern regions.

According to the agriculture ministry, 23 million tonnes of paddy straw is burnt in Punjab, Haryana and UP every year.

 

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How Harbour seals navigate at night?

Indian and Polynesian sailors have historically been guided by lodestars to find their way at sea. But research shows that harbour seals have been doing it much before humans attempted it. Harbour seals are marine mammals. They live along the Atlantic and Pacific coastlines of the Northern Hemisphere, and hunt for food at night. Obviously, in the dark, they cannot follow the landmarks that are visible on land.

In 2006, German and Danish scientists placed two harbours seals – named Nick and Malte – in a specially constructed floating planetarium. The team trained the two to swim in the direction of specific lodestars. They discovered that the animals could identify a single star out of a projection of the Northern Hemisphere night sky. This showed that the seals followed specific lodestars as navigational aids when they swam far from the shore. Remember, this was an experiment. So do the seals in the wild navigate by following individual stars? Researchers believe they do. Star-based navigation enables the seals to efficiently search an area for food.

 

Picture Credit : Google

How birds navigate at night?

Scientists say migrating birds rely on the magnetic compass after sunset. They also use the individual stars for navigation at night. All animals with “camera eyes”, the kind of eyes humans have, can make out individual stars. Insects with compound eyes cannot do this so they see the starry sky and the Milky Way as patterns of light. But scientists do not have an answer for one question: how do birds flying at night change the point of reference when they cross the equator? How do they follow the stars that change their orientation across the equator?

One example of birds that understand stellar navigation is the indigo bunting of North America. These birds fly south for winter, and they do it at night. There is less competition for food at night and there are fewer disturbances after dark. In one experiment, researchers captured these migrating birds and placed them under a starlit dome. And this is what they found.

Indigo buntings watch the rotation of close star patterns around a centre point, such as the North Star. From this they determine the directions. Before migrating, songbirds orient themselves by hopping in the direction they want to travel. In the experiment, the starlit dome rotated around the North Star, which is what happens in the night sky. The smart birds observed it and began to fly south. Then the researchers removed the constellations within 35 degrees of the North Star. The birds became disoriented and couldn’t fly anywhere.

So, individual stars are not that important for the birds. What they need to see is the rotation of the close star patterns around a centre point. This helps them to determine where north is. They use this information to fly south.

 

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How Dung beetles navigate at night?

Whenever we talk of the navigational skills of explorers, we wonder: How did these seafarers find their way about the sea with no navigational aids like sat-nav? The answer is always the same. Sailors of olden days followed the stars. They understood star formation and aligned their route to how the stars appeared in the night sky. But man is not only the creature that “followed the stars.” Sea creatures and birds are known to have looked up to the heavens for guidance. Recent studies in this field show that dung beetles too use the stars for navigation! And they have a brain the size of a grain of wheat!

Dung beetles are African insects. During the day, the beetles walk in a straight line rolling the dung. The beetles survive because of the dung. The dun provides them with food and drink, and during the hot African noon, the beetles simply climb on the dung to keep themselves cool. So the beetle fights for the smallest bit of dung, and carries it away even during the night.

At night, moonlight is their guide. On the days the moon is not visible, dung beetles follow the Milky Way. Human, birds and sea creatures follow just the lodestar. Just one star is enough for them. But the eyes of the dung beetle are not that sharp. The Milky Way has a straight band that is easy for the beetles to follow. For the Milky Way to be seen, the sky has to be clear. So, should we not keep the sky clear, without pollution, so the poor beetles trying to cart their food do not lose their way?

 

Picture Credit : Google

What was the first jukebox?

How do you carry your music? You probably have it stored in your mobile phone or use music apps to stream them and listen. If you still don’t have your own smartphone, then you might be using a music player or the radio to listen the songs whenever you want. What if none of these options was possible? What if you had to gather around a device that played music, paying for every time you used the service?

A jukebox is a semi-automated music-playing device popular in the middle of the 20th century. Usually a coin-operated machine, it played a user’s selection from available self-contained media. If the idea doesn’t seem relatable to you, wait till you hear about a nickel-in-the-slot phonograph.

First jukebox

The nickel-in-the-slot phonograph is seen by many as the first jukebox, even though it was never known by that name (the word “jukebox” seems to have originated only after the 1930s). it was first installed on November 23, 1889 in the Palais Royale Saloon, Sutter Street, San Francisco, meaning it appeared nearly four decades before the word “jukebox” started doing the rounds.

Before we look at the nickel-in-the-slot machine, we will have to understand the phonograph. The brainchild of American inventor and businessman Thomas Edison, it was first demonstrated by him in 1877. Even though Edison firmly believed that his phonograph – a device for mechanical recording and reproduction of sound – would be put to use in offices, it was the music industry that benefited most from it.

Phonograph at its core

Among those who made the most of the phonograph were two men, Louis T Glass and William S Arnold. Glass worked with the Pacific Phonograph Company during that time and Arnold was his business associate. Glass was struck with the idea that if he could get people to part with money to listen to music, he might make it big in a new business. He soon got to work along with Arnold, and he proved to be absolutely right about his ideas.

Glass and Arnold came up with the nickel-in-the-slot phonograph, an inventions that placed on Edison Class M electric phonograph inside a wooden cabinet. With loudspeakers yet to be invented, the phonograph was attached to four tubes that looked like stethoscopes that were used to listen to the only song stored in the device.

Glass particularly prided himself in the way in which he had devised these four tubes. Each of these tubes was provided with a slot in which a nickel (coin) could be dropped. While dropping a nickel in any of these slots started the machine and played the song, it was only audible in the tube in which the nickel was dropped. If others tried to listen in with the other tubes, they got no sound, unless they dropped a coin to activate that tube as well.

Once installed at the Palais Royale Saloon, it became evident that it was an instant success. With minimal amounts being spent for regular maintenance, it was clear that Glass and Arnold had struck it rich. To add to that, the machines turned out to be so attractive that places that wanted to be buzzing with people took it on lease on regular rentals, while receiving just a 10th of the actual proceedings.

Makes a lot of money

Six months from the time the first nickel-in-the-slot phonograph got going, on May 14, 1890, it had raked in $1,035.25 1(a lot of money at that time). Other machines that had been placed around the city, including some that were placed in close proximity to each other, also did equally well. This prompted Glass to say “that all the money we have made in the phonograph business we have made out of the-nickel-in-the-slot machine,” when he was invited to speak at the first annual convention of local phonograph companies of the U.S. held in Chicago on May 28 and 29, 1890.

Till the advent of radio, phonograph and the various inventions based on it remained the mass medium for popular music and recordings. It was then followed by jukeboxes that dominated the scene until transistors were invented. They might have gone by a different name, but the predecessor to these jukeboxes started out by accepting just a nickel in the slot.

 

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How animals cope with a flaming forests?

Natural phenomenon

Wildfires or forest fires are a common natural occurrence. They start during the summer months when vegetation dries out. Lighting striking a dried tree is enough to start a blaze. Fanned by the wind, the fire spreads quickly, consuming vast areas of forest. Forest departments and firefighters have a tough job containing the fires and millions are spent and lives lost in extinguishing them.

Animals that live in regions that see frequent forest fires have evolved and adapted to live with it. Animals caught in a forest fire obviously try to escape the flames and break over. Predators seize this golden opportunity to grab a snack. Bears, raccoons, and raptors have been observed hunting down the fleeing animals.

Different species use different strategies to avoid being instantly barbecued. Birds fly away. Mammals run. Amphibians and other small creatures burrow into the ground, hide out in logs, or take cover under rocks. Other animals, including large ones like deer, or take refuge in water bodies.

Bush firefighters in Australia have frequently spotted waves of creepy crawlies rushing ahead of the fire, desperately attempting to outrun the licking tongues of flame.

Smoked out

Some animals die of smoke suffocation or are charred. These are the ones that can’t run fast enough or find suitable shelter. Not all of those creepy crawlies may escape. Young and small animals are particularly at risk and some of their strategies for escape might literally backfire. For example, a koala’s natural instinct is to crawl up into a tree and it ends up trapped.

Deep down

The heat can kill even organisms buried deep in the ground, such as fungi. Jane Smith, a mycologist with the U.S. Forest Service in Corvallis, Oregon, has measured temperatures as high as 700°C beneath in a wildfire, and 100°C a full 5 cm below the surface.

Scientists don’t know the exact number of animals that die in wildfires each year. However, there are also no documented cases of wildfires – even the really bad ones – wiping out entire populations or species.

Rising from the ashes

Landscapes burned in a wildfire don’t die. They just transform into a new habitat. This can also mean new opportunities. In some places, woodpeckers will fly in and feast on bark beetles in dead and dying trees. Black fire beetles lay their eggs only to burned-out trees since there is no sap or resin to trap the larvae when they emerge.

A disturbance like a wildfire lets an old forest be reborn. A fire sparks many changes, as plants, microbes, fungi, and other organisms re-colonize the burned land.

Water bodies in a burned area can also change. Fish may temporarily move away. There can be a short-term dying out among aquatic invertebrates, which can affect the land animals that eat them.

Woodland and grassland animals (and plants) have lived with a cycle of fire and re-growth for ages. Many species actually require fire to regenerate. Heat from the flames can stimulate some fungi, like morel mushrooms, to release spores. Certain plants will produce seeds only after a blaze.

Good or bad?

Over the past century, wildfires have often been put out quickly or prevented because they damage human habitation.

That’s led to fewer species of those trees and plants that grow only in the years after a fire. It’s also caused a fall in some animal species that depend on post-fire habitat. The Kirtland’s warbler is a small American songbird that nests only in young jack pine forests. The pine comes only release their seeds in a fire. Without fire, much of the bird’s nesting habitat has disappeared.

 

Picture Credit : Google