ANCIENT TIME-KEEPING DEVICES THAT KEEP TRACK OF EARTH'S MOVEMENTS AROUND THE SUN

 How Sundials tell time

Humans have used the Sun to monitor the passing of time for thousands of years. For example, Stonehenge is believed to have been erected around 2,500 BCE, constructed in such a way that each stone aligns with the Sun’s rise during the summer solstice and the sunsets of the winter solstice.

However, like so many other technological inventions, the timekeeping sundial seems to have emerged from the minds of ancient Egyptians. The first evidence of a sundial dates back to around 1,500 BCE and was composed in two parts of an L-shaped shadow-casting device to determine the time of day. Over time, different versions of the sundial emerged, such as the ancient Greek hemispherical sundial around 280 BCE and the portable sundials created in Rome around 164 BCE. By the 8th century BCE, more accurate shadow-clocks that you might recognise today were commonly used.

As Earth rotates on its axis, the Sun appears to move across the sky, rising in the east and setting in the west. Along its journey, the Sun’s light beats down over the world and casts shadows in places it can’t reach. Taking advantage of light’s inability to pass through solid objects, sundials use the shadow of a central stick, called a gnomon, to pan across a series of numbers, like a clock face, to indicate what time it is based on the Sun’s position in the sky.

There are, however, several criteria a sundial has to meet before it can accurately tell time, so it’s not always as simple as pressing a stick in the ground and surrounding it with stones. For a sundial to accurately tell the time, the gnomon needs to align with Earth’s vertical axis, which is tilted to 23.5 degrees, and point either truth north or true south depending on which side of the equator it’s on. The gnomon is positioned on the dial plate at an angle that matches Earth’s axis, which is also equal to the latitude of its location. For example, in Europe, sundial gnomons are placed at an angle of between 40 and 60 degrees on a horizontal dial plate.

GIANT SUNDIAL

When you think of a sundial, the image of a small, sun-drenched ornament at the bottom of the garden might spring to mind. However, in some parts of the world, sundials are enormous structures. The largest sundial in the world is the Samrat Yantra, a 27-metre-tall edifice built in Jaipur, northern India during the 18th century. The gigantic sun clock, also called the ‘supreme instrument’, is a part of a series of 19 astronomical instruments that form the Jantar Mantar observatory. Made from stone and marble, the Samrat Yantra has a central gnomon in line with Earth’s axis and two adjacent quadrants on either side, running parallel with the equator. When the Sun hits the gnomon, a shadow is cast on scales at either quadrant, indicating the time with an accuracy of within two seconds.

CLOCKING IN

Measuring the passage of time by keeping tabs on Earth's rotation

1 HOUR LINES

The shadow crosses a series of numbers that represent the hours on a clock.

2 SPACING THE NUMBERS 

Each number is exactly 15 degrees apart, which correlates to the 15 degrees of rotation Earth completes in one hour.

3 GNOMON

The shadow-casting gnomon is angled towards either the true north or true south.

4 DIAL PLATE 

Most dial plates are horizontal circular plates, parallel to Earth's axis of rotation. However, there are vertical alternatives that require the gnomon to point to the equator rather than the poles.

5 ANGLE

The angle that a gnomon sits on a sundial should correlate with the latitude of where it's placed. For example, in the UK a gnomon is angled around 52 degrees.

6 PATH OF THE SUN

As Earth rotates, the Sun passes through the sky, rising in the east and setting in the west.

SUNDIALS IN SPACE

Distinguishing between colours on the Red Planet can be a tricky business for a space rover when it’s trying to take a picture. Therefore, the onboard cameras need to be calibrated so that scientists can see if rocks are really red or not. To do this, NASA has employed an ancient technology to calibrate its cameras: the sundial. In place of the numbers used on a traditional time-telling sundial, a series of colours, such as red, blue, green and yellow, sit around the dial. When sunlight causes the central gnomon to cast a shadow, it points to one of the colours on the dial. Scientists back on Earth make note of what colour is shown on the sundial and use it to colour-correct images that the rover takes. 

DO YOU KNOW

 HOW DIALYSIS MACHINES WORK?

Without healthy kidneys, your body would quickly fill with toxins, causing it to shut down. To prevent this buildup, these two fist-sized organs are continuously working to filter out waste substances from biological processes and pass them out of the body in your urine. For people who suffer from kidney failure, an alternative method is needed to emulate this essential task. Dialysis machines, which were invented in 1943, divert blood out of the body to be cleaned before being returned to the body. Because the body is continually producing waste, patients who depend on dialysis usually undergo four hours of treatment approximately three times a week.

During the process, the machine is attached to a needle, often placed in the arm, through which blood can be extracted and returned. As the blood enters the dialysis machine, it passes along a layer of membranes. These membranes have microscopic holes that only water and waste molecules can filter through. Because of this, no blood cells are lost to the machine – they simply take a diversion on their circulatory course.

The dialysis machine’s fluid, called dialysate, consists of water, electrolytes and salts. Mimicking the concentration of body fluid found outside of your body’s cells, dialysate draws waste products across the membrane in a process called diffusion. Because the waste molecules are in higher concentrations in the blood, they pass from an area of high concentration to an area of low concentration. When the blood is returned to the vein, it’s in a similar condition to filtered blood that has passed through the kidneys.

INSIDE AND OUTSIDE THE BODY

There are two types of dialysis: haemodialysis and peritoneal. The former involves an external dialysis machine, while peritoneal dialysis takes place mostly inside the body. Dialysis fluid is pumped into a space in the abdomen known as the peritoneal cavity, and the membrane lining the abdomen carries out the usual role of the kidneys. Waste products diffuse out of the blood and into the abdominal cavity, ready to be pumped back out of the catheter tube into a separate bag. This form of dialysis is ideal for people who need regular treatment and want to fit it around their busy schedules. Instead of clocking significant hours in hospital while hooked up to a haemodialysis machine, portable peritoneal dialysis machines can be used at home or while travelling.

REMOVING WASTE

How haemodialysis cleans the blood:

1. CATHETER

A tube is inserted into a large vein in either the leg, arm or chest.

2. ARTERIOVENOUS FISTULA

A surgeon carries out a procedure to connect an artery and vein together. This creates a strong site for dialysis.

3. PRESSURE MONITORS

When too much fluid is removed from the blood, patients can suffer from low blood pressure. This monitor sounds an alarm when this occurs.

4. BLOOD PUMP

This device drives blood around the dialysis machine when outside the body, directing blood out of and back into the body.

5. HEPARIN PUMP

A blood-thinning medication called heparin is added to the blood through a syringe. Heparin prevents the blood from clotting when outside the body.

6. DIALYSER

Membranes in the main machine filter waste products out of the blood, but keep blood cells separate from the dialysis fluid.

7. WASTE DIALYSIS FLUID

Waste drains out of the blood, through a membrane, into a bag.

8. CLEAN DIALYSIS FLUID

Fresh dialysis fluid is pumped in the opposite direction of the blood flowing through the machine.

9. AIR TRAP

This device detects any air in the blood and prevents it from passing into the body.

5 FACTS REASONS FOR DIALYSIS:

1. DIABETES

Diabetes is a condition that can lead to high blood sugar. Over time this can cause damage to the kidneys’ blood vessels, preventing the organs from working well.

2. HYPERTENSION

High blood pressure causes blood vessels in the kidneys to narrow, weakening them over time and reducing the kidneys’ function.

3. INFLAMMATION

Infections can cause inflammation of the kidneys. Inflamed kidneys leak proteins into urine, stopping it from absorbing water from body tissues.

4. CYSTS

When fluid-filled sacs form in the kidneys, the membranes they protrude from are unable to filter waste from the blood.

5. INHERITED DISEASE

There are around 300 genetic kidney disorders. Some of these conditions require the use of dialysis machines.

A FISH THAT DOES NOT HIDE ANYTHING THAT LIES INSIDE

 X - ray tetra fish

There are many strange creatures in Nature. The X-ray tetra fish is one of them. It is a small fish that does not hide anything that lies inside. The most distinctive feature of the fish is its translucent layer of skin. One can see everything including its vertebral column and its spine. If there are eggs inside the body, they can also be seen. The body of this fish is like an X-ray film, hence the name X-ray tetra.

The X-ray tetra is also known as the Golden Pristella Tetra or the Water Goldfish due to the faint golden colouration of its translucent skin. This freshwater fish is found in Amazon and Orinoco rivers, and their tributaries, in South America.

It is also found in coastal rivers and swamps in Venezuela, Guyana, Suriname and French Guyana. It is one of the most popular fish found in aquariums today. This small fish has the rare characteristic of being able to live in different types of water bodies.

X-ray tetra has golden stripes and yellow, black and white fins. It can capture the sound waves in the water.

These fish live in large groups in the deep parts of the water and eat insects, small creatures and aquatic plants but are primarily predatory. Their main enemies are large fish and frogs. Their transparent body is a gift of Nature to avoid being easily spotted by their predators. It is not easy to find X-ray tetras among the countless plants in the water.

The young one of the tetra fish is called fry. The female X-ray tetra lays 300 – 400 eggs by scattering them amongst dense vegetation. The fry begins to hatch as early as 24 hours later, and starts swimming within a few days.

POPULAR AND VERSATILE HOUSEPLANT

Pothos or Money Plant

Pothos or money plant is a popular and versatile houseplant popular for its beautiful trailing vines and ease of care. While most types are primarily grown indoors, some can also thrive outdoors in warm and humid climates. 

Why are pothos famous as money plant in India?

 In India the pothos plant is commonly popular as the Money Plant due to its strong association with wealth and prosperity in traditional beliefs such as Feng Shui and Vaastu Shastra. Here are more reasons why it is famous in India. 

Symbol of abundance and growth: The lush and vibrant appearance of the plant makes it a powerful symbol of abundance and growth. Its attractive foliage and trailing vines are often associated with prosperity and thriving conditions, further reinforcing its connection with wealth. 

Auspicious heart-shaped leaves: The heart-shaped leaves of the plant are deemed highly auspicious, as they resemble coins. This visual similarity to money strengthens the belief that having a pothos plant will attract financial fortune and prosperity. 

Positive energy, air-purifying qualities: Pothos is highly valued for its air-purifying qualities, making it a popular choice for indoor decorations. In addition to this, it is believed to bring positive energy and harmony to the surroundings, promoting a sense of well-being and prosperity. 

Cultural and traditional beliefs: While the belief in pothos' money-attracting properties is widespread in India and other regions, it is essential to acknowledge that these beliefs are based on cultural and traditional practices rather than scientific evidence. Nevertheless, the popularity of pothos as a 'Money Plant' endures due to its positive symbolism and easycare nature. It's important to note that while pothos is a beautiful and popular houseplant, the belief in its money-attracting properties is based on cultural and traditional beliefs rather than scientific evidence. Nevertheless, pothos remains a cherished and widely loved plant in many Indian households and is admired for its lush foliage and easycare nature.

11 TYPES OF MONEY PLANTS:      

1. GOLDEN POTHOS: 

Botanical name: Epipremnum aureum 

Itis one of the most common type, with heart-shaped green leaves streaked with golden-yellow variegation.

2. MARBLE QUEEN POTHOS

Botanical name: Epipremnum aureum 'Marble Queen' 

Marble money plant features large, glossy leaves with green and white marbled variegation, making it a popular types choice.

3. JESSENIA POTHOS: 

Botanical name: Epipremnum aureum 'Jessenia'

This variety displays deep green leaves with a hint of golden-yellow variegation, making it an intriguing types.

4. MANJULA POTHOS:

Botanical name: Epipremnum aureum 'Manjula'

A striking variety with green leaves that have silvery-white variegation and irregular edges, making it a unique money plant selection.

5. N'JOY POTHOS:

Botanical name: Epipremnum aureum N'Joy' Known for its small, heartshaped leaves with green centres and white edges, making it a delightful types to grow.

6. PEARLS AND JADE POTHOS:

Botanical name: Epipremnum aureum 'Pearls and Jade' 

A unique variety with green leaves speckled with white and cream-coloured spots, adding interest to your different types of money plant collection.

7. SNOW QUEEN POTHOS:

Botanical name: Epipremnum pinnatum 'Snow Queen' 

Features leaves with green centres and white-silver variegation, a wonderful types of money plant.

8. SILVER SATIN POTHOS:

Botanical name: Scindapsus pictus 'Satin Pothos'

Although not a true pothos, it is a similar trailing plant with heartshaped leaves featuring silver markings, a captivating types of money plant look-alike.

9. GOLDEN DRAGON POTHOS: 

Botanical name: Epipremnum aureum 'Golden Dragon'

This variety displays green leaves with golden-yellow variegation, creating a dragon-scale pattern, a fascinating choice for a money plant enthusiast.

10. CEBU BLUE POTHOS: 

Botanical name: Epipremnum pinnatum

A cultivar with green leaves and striking splashes of creamy-white variegation, adding charm to your unique types of money plant collection.

11. BLACK MONEY PLANT:

Botanical name: Epipremnum aureum 

This is a popular indoor plant known for its striking dark green and silver variegated leaves. Its lush and resilient foliage adds a touch of elegance to interior spaces while requiring minimal care.

NOTE: Please note that some of these types of money plant in India may have various common names or be sold under different names by nurseries or retailers. 

When growing pothos, it's essential to provide them with well-draining soil, indirect light, and regular watering to keep them healthy and thriving. 

PINK WATERS

 Retba Lake

Imagine you had to dive into a giant pool of strawberry milkshake! Yummy and refreshing, isn’t it? Such a thing does not exist. But there is a pink lake that lies 30km northeast of Dakar, the capital of Senegal called Retba lake, also known as Lac Rose. Its fuchsia-pink waves lap up against crystalline white shores, conjuring an unusual sight. Believe it or not, it is a natural phenomenon. 

The 3 sq.m. lake is separated from the Atlantic Ocean by a narrow strip of dunes. This contributes to the high levels of salt in the lake, comparable to the levels present in the Dead Sea. The high salinity makes the lake a perfect habitat for a kind of micro-algae called Dunaliella salina. The organisms produce a red pigment that absorbs and uses sunlight to create more energy, turning the waters pink. 

The high concentration of salt contributes to a flourishing salt industry. Salt miners scrape the bottom of the 3m-deep lake for salt, take the sludge ashore in wooden canoes and lay it out in mounds to procure salt. The workers cover themselves in shea butter to protect their skin against the harsh waters. Tourists visit Retba Lake not only to see the oddity of nature, but also to enjoy a buoyant experience  - floating on the lake like on the Dead Sea. 

Many other countries around the world have natural pink lakes; including Canada, Spain, Australia and Azerbaijan.

 

GRAB THE OPPORTUNITIES IN LIFE

 Never miss an opportunity

A young man wished to marry the farmer’s beautiful daughter. He went to the farmer to ask for her. The farmer looked at him and said, “Son, go stand out in that field. I’m going to release three bulls, one at a time. If you can catch the tail of any one of the three bulls, you can marry my daughter.”

The young man stood in the pasture awaiting the first bull. The barn door opened and out ran the biggest, meanest looking bull he had ever seen. He decided that one of the next bulls had to be a better choice than this one, so he ran over to the side and let the bull pass through the pasture out the back gate. 

The barn door opened again. Unbelievable! He had never seen anything so big and fierce in his life. The bull stood pawing the ground, grunting, slinging slobber as it eyed him. Whatever the next bull was like, it had to be a better choice than this one. He ran to the fence and let the bull pass through the pasture, out the back gate. 

The door opened a third time. A smile came across his face. This was the weakest, scrawniest little bull he had ever seen. This one was his bull. As the bull came running by, he positioned himself just right and jumped at just the exact moment. He grabbed... but the bull had no tail! 

Life is full of opportunities. Some will be easy to take advantage of, some will be difficult. But once we let them pass (often in hopes of something better), those opportunities may never again be available. So always grab the first opportunity that comes your way!

NATURAL WONDERS OF INDIA

 The Pulicat lake

The second largest saltwater lagoon in India, after the Chilika Lake, is the Pulicat lake, a brackish water lagoon, rich in floral and faunal diversity, that is spread over the Nellore and Thiruvalluvar districts of Andhra Pradesh and Tamil Nadu respectively. About 60 km in length, the lake is spread out over an area of 720 sq km, of which 84% lies in Andhra Pradesh and the remaining 16% in Tamil Nadu.

Pulicat lake is fed by three rivers– the Swarnamukhi from the north, the Kalangi from the northwest, and the Arani from the south – and some smaller streams. Aligned parallel to the coastline with its western and eastern parts covered with sand ridges, the lagoon is separated from the Bay of Bengal by a spindle-shaped barrier island named Sriharikota (on which the Satish Dhawan Space Centre, a satellite and rocket launch centre of the ISRO, is located).

Water flows into the lagoon from the sea through an inlet at the island’s northern end and back from the lagoon to the sea through an outlet channel at the southern end. Salinity of the water varies from season to season, reaching its highest during the pre-monsoon and post-monsoon months and lowest during the monsoon season.

The lake and its environs are steeped in history. Pulicat, under the name Podouke, is mentioned in ancient Greek and Roman records as an important port on the east coast of India in the 1st and 2nd centuries. In the 13th century, the shores of the lagoon became a refuge for Arab mariners who migrated here after being banished from Mecca. In subsequent centuries, the lagoon was colonised first by the Portuguese and then by the Dutch.

The Dutch East India Company set up a factory in the area in 1610, which was to be their principal trading post for the next 200 years. Later it was ceded to the British, who converted Pulicat into a fishing village and health resort.

Pulicat lake is considered a storehouse of rich biological resources, as it supports active commercial fisheries and a large and varied bird population. It is known to support 168 species of fish, including both seawater and freshwater species. Over 12000 fishermen and their families, residing in the vicinity, make their living on the catch obtained from the lake. 

Known for its diversity of aquatic birds, the lake is an important stopover on migration routes and is considered the third most important wetland for migratory shorebirds along the eastern coast. Resident and migratory waterfowl found here include pelicans, herons, storks, flamingos, ducks, shorebirds, gulls, terns and many species of raptors. The lake is a legally notified bird sanctuary, managed by the Andhra Pradesh and Tamil Nadu Forest Departments.

Today, the Pulicat lake faces several environmental and industrial issues threatening the biodiversity of the wetland and the livelihood of the fisherfolk. A major threat is pollution in the form of garbage (plastic bags and other non-biodegradable materials) dumped by tourists, oil spills from boats in the satellite port of Ennore creek, and industrial wastes, including toxic fly ash, discharged fromt he nearby thermal power station.