My Science School

You could be out in the middle of the ocean - surrounded by thousands of kilometres of water - and not have any water to drink when you’re thirsty. Why? Because ocean water is full of salt. If you did drink it, it would simply make you more thirsty.

The ocean is salty because rivers dump salt into it. All the rivers that flow down mountainsides and over the land tear loose tonnes of minerals. Most of these minerals are different kinds of salts. The rivers carry these salts to the ocean.

There’s never enough salt in most rivers to make the river water taste salty. But rivers have been dumping salt into the ocean for millions of years. By now, there is enough salt in the ocean to cover all of the land on the earth with a layer of salt hundreds of metres deep!

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Land on the Earth

The earth is a huge ball, but it is not smooth all over like a ball that you bounce or roll. The earth’s surface is full of bumps and dips, but some parts of it are smooth. Where there’s no water, there is land.

Some of the earth’s surface is on the ocean floor. You live on one of the earth’s continents - or maybe on an island. You may live on a mountain, in a valley, on a plain, or in a desert.

Land is the solid surface of the Earth that is not permanently covered by water. The vast majority of human activity throughout history has occurred in land areas that support agriculture, habitat, and various natural resources. Some life forms, including terrestrial plants and terrestrial animals, have developed from predecessor species that originated in bodies of water.

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Dennis the Menace is a daily syndicated newspaper comic strip originally created, written, and illustrated by Hank Ketcham. It debuted on March 12, 1951, in 16 newspapers and was originally distributed by Post-Hall Syndicate.

Dennis Mitchell, nicknamed Dennis the Menace, has messy blond hair with a characteristic cowlick in the back. He was initially depicted as a defiant child who deliberately sought out mischief, but over the years his personality softened considerably. He does not mean any real harm, yet he cannot help creating a racket or a mess at home, making a scene in public, and driving his parents, Alice and Henry Mitchell, to distraction.

The most frequent target of Dennis’s mischief is George Wilson, an older neighbour whom Dennis seldom allows a moment of peace, having adopted him as a surrogate grandfather. Wilson’s wife, Martha, obligingly behaves like an indulgent grandmother. Among the minor characters in the strip are Dennis’s shaggy dog, Ruff, and his toddler sidekick, Joey McDonald. Dennis’s nemesis is the slightly older and gratingly superior Margaret Wade, and he harbours a secret crush on the tomboyish Gina Gillotti.

The inspiration for the comic strip came from Dennis Ketcham, the real-life son of Hank Ketcham, who was only four years old when he refused to take a nap and somehow messed up his whole room. Hank tried many possible names for the character, and translated them into rough pencil sketches, but when his studio door flew open and his then-wife Alice, in utter exasperation, exclaimed, "Your son is a menace!", the "Dennis the Menace" name stuck. The character of Henry Mitchell bore a striking resemblance to Ketcham. The Mitchell family of Dennis, Hank/Henry, and Alice were all named after the Ketchams.

Ketcham received the Reuben Award for the strip in 1953. He also was made honorary mayor of Wichita. He was quoted as saying, "I set the whole thing in Wichita, Kansas, and as a result I got made an honorary mayor of Wichita."

 

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Popeye is the main protagonist of the Popeye Franchise, a sailor character created in 1928 by Elzie Crisler Segar for his Thimble Theatre comic strip (subsequently renamed after Popeye himself). The star of many comics and animated cartoons, he is best known for his squinting (or entirely missing) right eye, huge forearms with two anchor tattoos, skinny upper arms, and corncob pipe. He can occasionally be seen smoking his pipe but usually he toots it like a tugboat and sometimes uses it as a weapon by blowing the smoke in his enemies faces. His strength varies among his portrayals: as per the original comics, he is super-humanly strong and can lift huge objects, while in later adaptations he is not quite as mighty until he gains a boost in strength by eating spinach. He is known to mutter when he speaks and mangle the English language (e.g, he calls elephants and infants "elephinks" and "infinks", respectively). Popeye's creator, E. C. Segar, characterized him as violent and uncivilized yet introspective and with a high moral fiber.

Popeye has a long and rich history spanning nearly a century and is one of the most recognizable and beloved cartoon characters in the world, consistently regarded as one of the best ever created.

Popeye's exploits are also enhanced by a few recurring plot elements. One is the love triangle among Popeye, Olive, and Bluto, and Bluto's endless machinations to claim Olive at Popeye's expense. Another is his near-saintly perseverance in overcoming any obstacle to please Olive, who often (if temporarily) renounces Popeye for Bluto.

 

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Garfield is a fictional cat and the protagonist of the comic strip of the same name, created by Jim Davis. The comic strip centers on Garfield, portrayed as a lazy, fat, and cynical orange persian/tabby cat. He is noted for his love of lasagna and sleeping, and his hatred of Mondays, fellow cat Nermal and exercise.

Garfield is an overweight anthropomorphic orange tabby noted for his laziness, smug sarcasm, and intense passion for food, particularly lasagna, pizza, and ice cream. Throughout the course of the strip, Garfield's weight is often an object of ridicule, particularly by his talking electronic scale. Garfield usually does not handle insults or commands from the scale (or anybody else) very well, and will normally respond to such remarks with violence or a comeback of some type.

Garfield lives with his slightly eccentric, socially awkward owner Jon Arbuckle and Jon's unintelligent pet dog Odie, and enjoys satirically teasing them. He particularly enjoys causing Odie physical harm or insulting him, and teases Jon for his social awkwardness and unpopularity with women. Despite this, Garfield cares for Odie and Jon, but cares most for his beloved teddy bear Pooky, which is frequently seen in his arms or close to its owner.

 

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Hobbes' dual nature is a defining motif for the strip: to Calvin, Hobbes is a living anthropomorphic tiger, while all the other characters see Hobbes as an inanimate stuffed toy.

Calvin and Hobbes was conceived when Bill Watterson, while working in an advertising job he detested, began devoting his spare time to developing a newspaper comic for potential syndication. He explored various strip ideas but all were rejected by the syndicates. United Feature Syndicate finally responded positively to one strip called The Doghouse, which featured a side character (the main character's little brother) who had a stuffed tiger. United identified these characters as the strongest and encouraged Watterson to develop them as the centre of their own strip. Though United Feature ultimately rejected the new strip as lacking in marketing potential, Universal Press Syndicate took it up.

The final strip ran on Sunday, December 31, 1995.

As the final strip was run on a Sunday, it was in color. It depicted Calvin and Hobbes outside in freshly fallen snow carrying a sled. Reveling in the wonder and excitement of the winter scene, Hobbes says, "Everything familiar has disappeared! The world looks brand new!" Calvin agrees saying, "It's a magical world, Hobbes, ol' buddy!" Hobbes remarks about the fresh snow, "It is like having a big white sheet of paper to draw on!” Calvin adds, "A day of possibilities." Getting ready to sled down the hill, Calvin exclaims, “A new year...a fresh, clean start!” Calvin and Hobbes sled down the snowy hill, Calvin saying "Let's go exploring!"

According to a critic, speaking in 2005, "They left a hole in the comics page that no strip has been able to fill."

 

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Snoopy is an anthropomorphic beagle in the comic strip Peanuts by Charles M. Schulz. He can also be found in all of the Peanuts movies and television specials. Since his debut on October 4, 1950, Snoopy has become one of the most recognizable and iconic characters in the comic strip and is considered more famous than Charlie Brown in some countries. The original drawings of Snoopy were inspired by Spike, one of Schulz's childhood dogs.

Snoopy first appeared as a character balloon in the Macy's Thanksgiving Day Parade in 1968; the balloon depicted Snoopy in his World War I Flying Ace costume.

Snoopy appeared on the October 4, 1950, strip, two days after the first strip. He was called Snoopy for the first time a month later, on November 10. He was originally Patty's dog but quickly adopts Charlie Brown. On March 16, 1952, his thoughts were first shown in a thought balloon. Snoopy first appeared upright on his hind legs on January 9, 1956, when he was shown sliding across a sheet of ice after Shermy and Lucy had done so.

Woodstock is a fictional character in Charles M. Schulz's comic strip Peanuts. He is best known for being Snoopy's best friend and sidekick. The character first appeared in the April 4, 1967 strip, although he remains unnamed until June 22, 1970. He is named after the Woodstock festival of 1969.

In the early 1960s, Snoopy began befriending birds when they started using his doghouse for various occasions: a rest stop during migrations, a nesting site, a community hall, or a place to play cards. None of these birds was ever given a name, although they did, on occasion (e.g., July 10, 1962), use speech balloons, lettered in what would become the classic 'chicken scratch marks' of Woodstock's utterances. What set Woodstock apart from all these earlier birds was the fact that he attached himself to Snoopy and assumed the role of Snoopy's sidekick and assistant. There had been no recurring relationships between Snoopy and the earlier birds who visited the yard of the Browns, and Snoopy was as often as not more hostile than friendly toward those birds.

In the Peanuts daily comic strip on March 3, 1966, a mother bird flew in while Snoopy was lying on top of his doghouse, nested on top of his stomach and flew away. Soon afterward two chicks hatched in the nest, one of which hung around Snoopy throughout the spring, and returned the following spring on April 4, 1967. Schulz began to establish character traits for Snoopy's new friend by revealing that he could talk (or at least emote), that he didn't like flying south every winter, and that he struggled with flying. By the end of this four-strip sequence, Snoopy, in character as the World War I Flying Ace, learns that the bird is his new mechanic, Woodstock's first supporting role.

 

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The Cambrian explosion or Cambrian radiation was an event approximately 541 million years ago in the Cambrian period when practically all major animal phyla started appearing in the fossil record. It lasted for about 13 – 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversifications in other groups of organisms as well.

The rapid appearance of a wide variety of animals - particularly bilaterians - led to the development of radical new ecological interactions such as predation. Consequently, ecosystems became much more complex than those of the Ediacaran. As the number and variety of organisms increased, they occupied a variety of new marine environments and habitats. Cambrian seas teemed with animals of various sizes, shapes, and ecologies; some lived on or in the sea floor (a benthic lifestyle), while others actively swam in the water column (nektonic).

The fundamental ecological structure of modern marine communities was firmly established during the Cambrian. By the end of the Period, some animals had also made the first temporary forays onto land, soon to be followed by plants.

 

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The period is named after Devon, a county in southwestern England, where a controversial argument in the 1830s over the age and structure of the rocks found distributed throughout the county was eventually resolved by the definition of the Devonian period in the geological timescale. 

A fossil creature from the Devonian discovered more recently has been hailed as a vital link between fish and the first vertebrates to walk on land. Found in the Canadian Arctic in 2004, Tiktaalik had a crocodile-like head and strong, bony fins that scientists think it used like legs to move in shallow waters or even on land. The fish showed other characteristics of terrestrial animals, including ribs, a neck, and nostrils on its snout for breathing air.

Plants began spreading beyond the wetlands during the Devonian, with new types developing that could survive on dry land. Toward the end of the Devonian the first forests arose as stemmed plants evolved strong, woody structures capable of supporting raised branches and leaves. Some Devonian trees are known to have grown 100 feet (30 meters) tall. By the end of the period the first ferns, horsetails, and seed plants had also appeared.

 

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Biostratigraphy is the branch of stratigraphy that uses fossils to establish relative ages of rock and correlate successions of sedimentary rocks within and between depositional basins. A biozone is an interval of geologic strata characterised by certain fossil taxa. Such intervals are often defined by the first appearances (range bases), apparent extinctions (range tops/last appearances), or abundances of fossil index species. These key index species should be relatively abundant, short-lived taxa that are easy to recognise and as geographically widespread as possible. Widely used fossil groups include brachiopods, conodonts, dinoflagellate cysts, foraminifera, graptolites, nannofossil, spores and pollen and trilobites. Zonal schemes based on several different fossil groups can be used in parallel, and the zones can be calibrated to the absolute geological timescale using tie points to rocks which have been radio-isotopically dated.

There are several kinds of biostratigraphy. Formal biostratigraphy is concerned with the delineation of biostratigraphic zones, which are bodies of rock defined by the presence of selected nominal taxa (fossil species or groups whose name is attached to the biostratigraphic zone). A special kind of formal biostratigraphy is called biochronostratigraphy, which requires nominal taxa that are short-lived and thus their existence defines well a short interval of geological time. Informal biostratigraphy is concerned with using fossil taxa to help define ancient environments, a type of study called paleoecology (the study of ancient ecology preserved in sedimentary rocks).

 

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Ammonites, which evolved about 416 million years ago, were once the most abundant animals of the ancient seas. These sea creatures first appeared 415 million years ago in the form of a small, straight shelled creature, known as Bacrites. They quickly evolved into a variety of shapes and sizes including some shaped like hairpins. During their evolution the ammonites faced no less than three catastrophic events that would eventually lead to their extinction. The first event occurred during the Permian (250 million years ago), where only 10% survived. These surviving species went on to flourish throughout the Triassic, however at the end of this period (206 million years ago) they faced near extinction, when all but one species survived. This event marked the end of the Triassic and the beginning of the Jurassic, during which time the number of ammonite species grew once more. The final catastrophe occurred at the end of the Cretaceous period when all species were annihilated and the ammonites became extinct. This event apparently coincided with the death of the dinosaurs.

Based on the fossil record, ammonites came in a wide range of sizes and shapes, from smaller than an inch to as large as nine feet wide. Some ammonites had long, straight shells, while others had helix-shaped shells. Most species, however, had coiled shells lined with progressively larger chambers separated by thin walls called septa.

The many chambers of their shells likely helped these cephalopods glide through the planet’s warm, shallow seas. A thin, tubelike structure called a siphuncle pumped air through the interior chambers of the shell, which scientists believe helped provide buoyancy and move ammonites through the water. It’s unclear whether ammonites were very efficient swimmers, though.

Scientists believed that ammonites, like modern cephalopods, had soft body tissue with tentacles attached to their heads for catching prey. Fossil evidence indicates they had sharp, beaklike jaws to snare prey such as plankton, crustaceans, and other ammonites. They were also preyed on by larger reptiles and fish.

 

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Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research.

All continents during the Triassic Period were part of a single land mass called Pangaea. This meant that differences between animals or plants found in different areas were minor.

The climate was relatively hot and dry, and much of the land was covered with large deserts. Unlike today, there were no polar ice caps.

It was in this environment that the reptiles known as dinosaurs first evolved. Reptiles tend to flourish in hot climates because their skin is less porous than, for example, mammal skin, so it loses less water in the heat. Reptile kidneys are also better at conserving water.

Toward the end of the Triassic, a series of earthquakes and massive volcanic eruptions caused Pangaea to slowly begin to break into two. This was the birth of the North Atlantic Ocean.

 

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In the first Test between Pakistan and South Africa that took place in Karachi, Pakistan, late in January 2021, South African speedster Kagiso Rabada took his Test wickets tally to 200. He did it in style, as he became the third fastest, in terms of balls bowled, to reach the landmark.

Kagiso Rabada took three wickets in the first Test between Pakistan and South Africa. Even though it came in a losing cause, Rabada had something to celebrate as he became the third fastest, in terms of balls bowled, to reach 200 Test wickets.

All three of Rabada's wickets in the game came in the first innings. Rabada accounted for both of Pakistan's openers in the first innings. He had Abid Ali bowled, while Imran Butt was out caught, as Rabada took his tally to 199. His 200th wicket came when he cleaned up tail-ender Hasan Ali.

Rabada's numbers as he enters

The 200-wicket club

Having made his debut against India at Mohali in 2015, Rabada has raced to 200 Test wickets in just over five years.

Rabada might be the third fastest to 200 Test wickets in terms of balls bowled, but he comes only 13th in terms of matches played. Rabada reached the milestone in his 44th Test match. Pakistan's Yasir Shah (33), Australia's Clarrie Grimmett (36) and India's Ravichandran Ashwin (37) are the three fastest to 200 Test wickets, in tents of matches played.

Rabada has the best strike rate in the history of Test cricket for bowlers with 200 or more wickets - a phenomenal 41.1. Rabada's compatriot Dale Steyn, who finished his Test career with 439 wickets at a strike rate of 42.3, and Pakistan's Waqar Younis, who finished with 373 wickets at a strike rate of 43.4, come second and third in this list.

Sweating or perspiration is a natural way for the body to regulate its temperature. Humans have sweat glands in many parts of the body. What about animals? Sweat glands are found in most mammals. But they do not produce large amounts of sweat (exception being horse). For instance, dogs and cats produce small amounts of sweat through their paws. The overall distribution of sweat glands varies among primates – while the rhesus monkey has them on the chest, some macaque species and baboons have them over the entire body. But they do not sweat as much as humans, as their fur serves as the temperature regulator.

Mammals also resort to other methods to regulate body temperature. Pigs and hippopotamuses roll in the mud to cool themselves, while dogs pant.

Have you ever wondered about the secretion on the skin of the hippopotamus? It is not sweat.

Hippos secrete a reddish oily fluid, sometimes called blood sweat, from special glands in their skin. This fluid functions as a skin moisturiser and antibiotic.

 

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