My Science School

Humans became aware of bird migration - the journey of birds between their breeding and wintering grounds - long ago. However, there's still so much we do not know about this riveting phenomenon. But thanks to science, technology, and research, we also constantly gain newer insights. Here's a look at a recent discovery.

Just like us humans who have an internal system that guides our body on when to sleep, wake up. etc., birds too have a system in place that lets them know when it is time to migrate. Apparently, they also "inherit' from their parents the direction in which they   must fly to reach their destination. Apart from this, they have "at least three different compasses at their disposal: one allows them to extract information from the position of the sun in the sky, another uses the patterns of the stars at night, and the third is based on Earth's ever present magnetic field". And it is this last aspect that the recent discovery throws fresh light on.

While research revealed decades ago that birds possessed magnetoreception - the ability to detect the Earth's magnetic field - it was not clear so far how exactly it worked. This mystery was solved when scientists recently discovered that the levels of a certain protein - named Cry4 - present in the eyes of migratory birds spike up suddenly during the migratory season. When this protein comes in contact with blue light (which is scattered in Earth's atmosphere), it leads to a chemical reaction that helps the birds sense the Earth's magnetic field.

Did you know?

During the first migration, the route gets registered in the birds' brain - apparently, this helps them navigate their subsequent journeys "with an ultimate precision of centimeters over thousands of kilometers". It means they gain an additional resource they can dip into - a mental map, as it were. But, since this absent during the first trip, even a small mistake such as veering off course could be fatal for the young birds.

The levels of a certain protein- named Cry4-present in the eyes of birds spike up suddenly during the migratory season. When this protein comes in contact with blue light (which is scattered in Earth's atmosphere), it leads to a chemical reaction that helps the birds sense the Earth's magnetic field.

Picture Credit : Google 

Waterfalls are nature's magnificent creations. Nothing warms the cockles of your heart as watching the waters surging and leaping across mountains. From the world's highest uninterrupted waterfall to the chocolate-coloured waterfall, we bring you the most dazzling sights from across the world.

GRAND FALLS- ARIZONA

Grand falls is a waterfall right in the midst of a desert. The Grand Falls in Arizona are taller than the Niagra Falls. The water falling in many tiers across the cliff is a delight to watch. Its muddy cascade has earned it the name Chocolate Falls.

NIAGARA FALLS- USA/CANADA

Surging forth with a thunderous force, these falls make for a resplendent sight. The name means 'thunder of waters', denoting the loud, roaring sound the waters make as they dive A part of the falls is located in Canada, while another is located in the United States. The former is called the 'Horseshoe Falls' courtesy of its curved shape and the latter 'American Falls'.

ANGEL FALLS- VENEZUELA

Dropping from a height of 3,212 feet, the Angel Falls in Venezuela is the highest waterfall in the world. Pouring out from a flat-topped plateau Auyantepui, the falls are located in Canaima National Park. The falls are about 16 times the height of Niagara Falls. Set against the dense jungle and the green surrounds, the waterfalls are one of the major attractions in Venezuela. Angel Falls is named after Jimmy Angel, an American bush pilot, who crash-landed his four-seater airplane at the Auyantepui.

NOHKALIKAI FALLS, MEGHALAYA, INDIA

Plummeting from a height of 340 m. the Nohkalikai Falls is India's tallest plunge waterfall. Located at Cherrapunji in Meghalaya, India, the waterfall is all about drama and grandeur. There is also a tragic legend that backs the name of the falls. The waterfalls are apparently named after Likai, a Khasi woman. When translated from the local Khasi language. Nohkalikai means Jump of Ka Likai'.

VICTORIA FALLS - ZIMBABWE

This curtain of waterfalls dropping from a height of 108m into the gorge below makes one of Earth's greatest spectacles. Explorer David Livingstone named the falls after the reigning British monarch Victoria. The local name of the waterfall is 'Mosi-oa-Tunya' meaning 'smoke that thunders. It is called so because the sound of the falls can be heard from a long distance.

Picture Credit : Google 

With concerns about air pollution on the rise, what can we do to purify the air we breathe in at our homes? Let's learn about some indoor plants that can clean up the air considerably.

Air pollution is not merely an outdoor menace. The air we breathe in at home also contains high levels of pollutants. Besides biological pollutants like dust, fungi and allergens, solvents and chemicals in perfumes, hair sprays, air fresheners and furniture polish are also potential hazards. They release Volatile Organic Compounds (VOCs). Formaldehyde, carbon monoxide and nitrogen dioxides in the air lead to allergies, headache, dizziness and other health disorders. Here are some indoor plants that can clean up the air considerably.

Aloe vera

It is a succulent and perennial plant which belongs to the lily family though it looks like a cactus, with its thick fleshy leaves and thorns.

This common plant which people often hang outside their doors to ward off evil has the ability to filter benzene and formaldehyde. It requires ample sunlight but it is easy to grow and there are hundreds of varieties to choose from. Besides cleaning up the air, it has immense medicinal properties. The aloevera gel helps treat sunburn and tanning, and is good for treating pimples, too. It heals burns and several skin diseases like psoriasis, scabies, rashes and itches. Extracts from the juice are mixed with other herbs to make a drink that helps deal with gas and other stomach ailments.

Snake plant

It is so called because certain varieties have geometrically patterned scales like snakes. This indoor plant has sharp and pointed tongue-like leaves and so it is also called Mother-in-law's tongue! It removes toxins like formaldehyde, benzene and nitrogen dioxide from the air. An ideal bedroom plant, it requires little sunlight and water and is easy to maintain. There are more than 50 species of this evergreen plant.

Bamboo palm

This slow-growing plant which originated in Central and South America helps to eliminate carbon monoxide, xylene, benzene and formaldehyde.

It needs to be kept in a shaded area which gets indirect or filtered sunlight. It does not need much water. It is enough if the soil is kept moist. It produces small yellow flowers which have a nice aroma. It is not only beneficial but can also serve as an ornate plant with its attractive upright stalks and elegant fronds.

Money plant

This long-wandering plant is an effective air purifier, removing VOCS. Native to Asia and Australia, it is so called as it symbolises wealth and prosperity in the Chinese system of Feng Shui. This creeper grows well indoors, is durable and adapts to any condition.

Rubber plant, Peace Lily and Dracena are also suitable to fight pollution.

Spider plant

It cleans up the air of benzene, carbon monoxide and xylene. This tough plant has arching grass-like leaves. It has tiny white flowers and it is so called because baby plantlets dangle from the mother plant resembling spiders on the web.

It is a no-fuss plant and adapts to any environment.

Chrysanthemum

This seasonal plant has countless varieties. It brightens up the place with its colourful flowers. Chrysanthemums remove benzene and contain a natural insecticide called pyrethrum. The flower heads are harvested and ground into a powder for use as insecticide.

Ecological balance

Different plants thrive in different seasons. For instance, while one species flowers in May, another could come into bloom as late as September. Scientists say that this time lag is crucial. This is because a huge variety of plant species are all competing for the same resources like air, sunlight and soil. The fact that plants bloom at different times ensures that each plant gets adequate resources to grow well.

However, ecologists point out that pollution is changing world climate and could disrupt this fine ecological balance in the future. For instance, increased levels of carbon dioxide could stimulate grasses and wildflowers to flower at the same time although currently they flower at different times. Tests indicate that in the presence of higher levels of carbon dioxide, grasses flower later while wildflowers flower earlier, resulting in an overlap!

This means animals that munch on grass may have to wait longer for grazing while this sudden profusion of flowering plants could well deplete natural resources, perhaps even leading to the extinction of certain plant species that aren't tough enough to survive.

Picture Credit : Google 

As the name indicates, natural dyes are those obtained from naturally available sources. Though plants are among the most common sources of natural dyes, insects, fungi and minerals contribute too. As for plant sources, the options are plenty from leaves, seeds, and bark to flowers fruits, vegetables, and roots. And if you think the number of colours could be limited since they are of natural origin, here's a little surprise for you- the variety is almost endless. Different shades of red, green, blue, purple, and brown can all be obtained naturally!

A few common sources

Cochineal and lac insects are a source for shades of red. While the former is used largely in textile, the latter is used in ornaments and for wood finish. Shellfish plays an important role as a natural source for shades of purple. The use of all three goes back at least a few centuries.

One of the oldest and most widely used, indigo comes from a variety of flowering plants of the genus indigofera, and it's believed to have been in use since prehistoric times. Pomegranate rind, turmeric, onion skin, tamarind seed, myrobalan fruit, marigold, bluebellvine flower, annatto seed, teak leaf, and madder root are some of the sources of natural dyes. These dyes have a wide variety of application.

Where are natural dyes used?

Many Indian textile traditions originally used only natural colours-while some may embrace synthetic colours now, some continue the tradition. Such traditions include ajrakh and kalamkari. In addition, several everyday products, including soaps, bags, and baskets, lend themselves to natural dyes.

Since synthetic colours have been proven to cause skin and health concerns, natural dyes offer a much safer alternative for use in food, cosmetics, and medicine.

Just like textile traditions, several of our toy and art traditions have used natural dyes. These include Etikoppaka and Channapatna (toys), and Patachitra, Gond, Patua, and Warli (painting traditions). Many floor and wall art traditions across our country, practised and popularised exclusively by women, have traditionally used natural sources of colours such as rice flour, clay, red soil, cow dung, etc. These traditions include kolam, mandana, and aripana.

Why natural dyes?

Kinder to Earth: Since they are natural, the dyes are biodegradable, and disposing them of may not cause pollution. In the case of a plant source other parts of that plant may have their uses too, leading to waste reduction. Many of the sources are said to use less water when compared to synthetic dyes.

Gentle on humans: Many synthetic colours are said to contain chemicals that can harm our skin (through textiles, cosmetics, or toys) or internal organs (when consumed as food), both during the production stage and when used. Such chemicals are almost absent in natural dyes.

Tradition meets innovation: The traditional process of preparing, testing, and using natural dyes is labour-intensive, and the people involved are artisans in their own right. Add to this contemporary experiments, and what we have is a unique result that beautifully straddles the old and the new.

Did you know

• Synthetic dyes have their origins invariably in non-renewable petrochemical compounds, and are available in many forms such as liquid powder, pastes, or granule. So, they cost less and are more widely used than natural dyes. But they are not environment-friendly in the long run. Their effluents may cause harm to marine creatures
• Synthetic or artificial dyes were invented less than 200 years ago, becoming particularly popular around the time of the Industrial Revolution. And for thousands of years before that, our ancestors had used colours obtained only from natural and local sources.
• Our country has evidence of madder-dyed textiles found at Mohenjo-daro nearly 5,000 years ago, a clear indication of our ancient knowledge of dyeing fabric.

Picture Credit : Google