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Have you ever heard anyone say something only happened “once in a blue moon”? Did you know what they meant?
A “blue moon” is when one month of the year has two full moons in it, like January of 1999 which had a full moon on January 1 and another on January 31.
Because the phases of the moon usually only result in one full moon each month, a “blue moon” month with two full moons is a pretty special thing. That’s why people say something happens “once in a blue moon.”
Now, if one blue moon a year is special, think about this. The year 1999 had a blue moon in January, but it will have another blue moon in March because there will be full moons on March 2 and another on March 31.
Experts say that two blue moons in one year happens about every 19 years, so two blue moons in one year is really something that happens once in a blue moon!
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No, it’s not little green men. A team of NASA scientists has made a discovery that suggests that primitive life may have existed on Mars more than 3.6 billion years ago.
The team of scientists found many pieces of evidence, including possible fossils, that suggests that microscopic, bacteria-like organisms once lived on the planet.
The fossils were found in a Martian meteorite that fell to Earth 13,000 years ago. The rock is believed to have broken off from the planet 15 million years ago when a huge comet or asteroid struck Mars. For millions of years, the chunk of rock traveled through space until it encountered Earth’s atmosphere.
The largest of the possible fossils are less than 1/100th the diameter of a human hair. The egg-shaped and tubular structures are similar to microscopic fossils of the tiniest bacteria found on Earth.
These organisms may have existed on Mars 3.6 to 4 billion years ago, a time when it is believed the planet was warmer and wetter. The team’s findings indicate that living organisms may have assisted in the formation of carbonate minerals, also found in the meteorite. It is possible that their remains were fossilized in a fashion similar to the formation of fossils in limestone on Earth.
The team of scientists point out that they haven’t conclusively proven the existence of past life on Mars. They’re simply putting the information out into the scientific community to study and debate – and debate they will.
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I like it
What a good try
What a brainwave
You do work well
That\’s good work
You\’re a star
You are doing well
Well figured out
I like that
You are doing great
You\’ve done really well
Keep on trying
You show real promise
You have great ideas
You\’ve mastered it
Well thought out
You\’ve fitted a lot in
How imaginative you are
Good problem solving
What a perfect example
Well worked through
I\’m very proud of you
I\’m proud of your work
You are really tuned into work today
It\’s a pleasure to see you work like that.
One more attempt and you\’ll be there
You\’re work is improving
You are a pleasure to teach
That\’s good thinking
A very good try
You learn quickly
You\’ve got the hang of it
You\’ve done better than ever
That\’s a fine attempt
You\’re a problem solver
I couldn\’t have done better myself
You soon mastered that
You really stuck with it
You don\’t give up
You\’ve got that down to a fine art
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The ancient Greeks loved to compile lists of the marvellous structures in their world. Though we think of the Seven Wonders of the Ancient World as a single list today, there were actually a number of lists compiled by different Greek writers. Antipater of Sidon, and Philon of Byzantium, drew up two of the most well-known lists. Many of the lists agreed on six of the seven items.
The final place on some lists was awarded to the Walls of the City of Babylon. On others, the Palace of Cyrus, king of Persia took the seventh position. Finally, toward the 6th century A.D., the final item became the Lighthouse at Alexandria. Since the it was Greeks who made the lists it is not unusual that many of the items on them were examples of Greek culture.
The writers might have listed the Great Wall of China if then had known about it, or Stonehenge if they’d seen it, but these places were beyond the limits of their world. It is a surprise to most people to learn that not all the Seven Wonders existed at the same time. Even if you lived in ancient times you would have still needed a time machine to see all seven.
While the Great Pyramids of Egypt was built centuries before the rest and is still around today (it is the only “wonder” still intact) most of the others only survived a few hundred years or less. The Colossus of Rhodes stood only a little more than half a century before an earthquake toppled it.
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THE SOLAR SYSTEM
Mercury is the first planet from the sun, 36 million miles away from the sun and it has no moons. It is a small, rocky planet and very hot. It has dusty surface filled with craters. Mercury looks a lot like Earth’s moon. A year is 88 days long and one day on Mercury is as long as 59 days on Earth.
Venus is the second planet from the sun, 67 million miles away from the sun and has no moons. Venus is almost as big as the Earth and you can find it shining in the night sky. There is strong winds that blow Venus’s thick, yellow clouds around. A year on Venus is 225 days long and one day there is as long as 243 Earth days.
Earth is the third planet from the sun, 93 million miles away from the sun and has one moon. Earth is a ball of rock almost covered by oceans. It is not too hot and not too cold, just right for us to live on it. From space Earth looks like a blue ball covered with white clouds. Under the clouds you can see blue oceans and brown and green land. A year on Earth is 365 long and one day on Earth is 24 hours long.
Mars is the fourth planet from the sun. 141 million miles from the sun and has 2 moons. Mars is desert except for the ice caps at each end of the planet. It has tall mountains and deep canyons. The soil is full of rust and Mars looks red. Strong winds blow up big storms of red dust that makes the sky look pink. The nights are very cold on Mars. A year on Mars is 687 days long and one day is 24 1/2 hours long.
Jupiter is the fifth planet from the sun. 483 million miles from the sun and has at LEAST 15 moons. Jupiter is the biggest planet in the solar system. It is a giant ball of gass with a rocky center. No one has ever seen the surface of Jupiter, it is covered with thick clouds. These clouds are white, yellow, tan, orange, and red. Strong winds blow the clouds around. It is freezing cold at the top of the clouds and boiling hot in the center of Jupiter. There is a large red spot on Jupiter that scientists think is a giant storm. One year on Jupiter is as long as 12 years on Earth and one day is almost 10 hours long.
Saturn is the sixth planet from the sun and is 885 million miles from the sun. Saturn has at LEAST 22 moons. Saturn is a giant ball of colored gas with a rocky center. It is covered with a haze of clouds. Scientists don’t think it has a solid surface. Saturn has many pretty rings around it. These rings are made out of bits of ice and rock that go around the planet. Saturn is freezing cold at the top of the clouds and very hot in the center. A year on Saturn is as long as 30 years on Earth. A day is only 10 1/2 hours long.
Uranus is the seventh planet from the sun and 1 billion 779 million miles from the sun. It has 5 large ooms and 10 small ones. Uranus is a giant gas ball with a rocky center. It has rings that are thin and dark. Uranus looks blue-green in color. A thick haze covers the planet. Uranus tilts over on its side, and moves around the sun like a rolling ball. One year on Uranus is as long as 84 years on Earth. One day is 16 hours long.
Neptune is 2 billion 780 million miles from the sun and has at least 2 moons. Neptune is a large ball of gass with a center of rocks and iron. It looks greenish in color. This planet is covered with clouds and is very cold. A year on Neptune is as long as 164 years on Earth and one day is about 17 hours long.
Pluto is 3 billion 656 million miles from the sun and has 1 moon. Pluto is the smallest planet, and is the coldest spot in our solar system. A year on Pluto is as long as 250 years on Earth. A day is as long as 6 days on Earth.
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Painting with oils is a very fulfilling and relaxing hobby. So, if the only brush you’ve ever held in your hand is a hairbrush but you’re willing to learn or teach your child, read on. One doesn’t need to be a talented artist in order to paint with oils. Anyone with interest in art will be able to do a fairly reasonable job.
If you are a complete beginner, here’s what you will need in order to make an oil painting.
A bottle of turpentine
Turpentine is essentially for cleaning brushes. It can also be mixed along with the paint, to thin it. Paint mixed with turpentine is sometimes used as a first layer, because the paint gets thin and it dries quickly. Also, when painting, you will need to clean brushes frequently, so keep a rag by your side, dip your brush in the turpentine, wipe it, and use another colour.
A bottle of linseed oil
Linseed oil is not the only oil you can use, but is often the preferred choice of some art students. An artist normally mixes a little oil with the paint before applying it on the canvas. The more oil used, the longer the paint will take to dry. Remember, if the first layer is not completely dry, and you paint the second layer on it, and if the second layer dries before the first layer, the paint will crack.
A dipper is a device of two cups; one holds the oil, and the other holds the turpentine. The dipper has a hook at the bottom, and it hooks on to the palette.
The artist removes paint from the tubes on the palette, and also mixes colours on the palette. The palette has a hole on one side, through which your thumb goes. You thus hold your palette in one hand and paint.
Canvas and brushes
The size of the canvas depends on the size of the image your child wants to paint. Your child should ideally start out on a canvas that is not too large. She could try and make something not very complicated, like two squares on a white background, to give her a feel of the brush strokes, paints etc. The canvas should never be bare at any spot. Where the background is white, white paint needs to be used. As for the brushes, invest in a few large and medium size flat brushes, and a few thin and medium size round brushes.
Do you have to be good at sketching in order to be a good painter? Ideally, if you sketch well, it will definitely make painting easier, but being good at sketching is not a requirement if you’re just painting for your own pleasure and as a hobby. You can still make beautiful paintings, but it probably will mean some hard work, and you will find it easier to make copies of other paintings, rather than make something on your own. If you’re not good at sketching, just find a painting that you like, make a full page colour copy, and draw a line through the center, up to down, and side to side, to form a cross. Then, measure half again, and draw futher crosses. Do the same with your canvas. You will then find it easier to copy the sketch. Remember, however, that the canvas should be proportionately bigger than the original, or your sketch will be skewed. Your child can sketch the image with pencil, or directly make the outlines with his paintbrush if he is more comfortable.
The only way to improve is practice. So, initially you or your child may mess up when mixing colours, but gradually you will improve. Your strokes, blending ability, will all fall into place with practice.
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When you checkout from a supermarket, the person at the counter checks all that you have bought by flashing a small light at a set of lines marked somewhere on every item. How does this system of checking work?
A barcode is machine-readable information. It allows data to be collected accurately and rapidly about the product such as what product it is, the country where it was manufactured, prices, stocks left and so on.
A Barcode symbol consists of a series of parallel bars and spaces. Each of these wide and narrow bars and spaces in the pattern represents a character which in turn represents some kind of a code. Such as, numbers 00-13 is the country code for USA and Canada, 45 for Japan and 890 for India.
How is the barcode read?
A barcode reader uses a scanning device which is basically a photo sensor. It measures the relative widths of the bars and spaces, translates the different patterns back into regular characters, and sends them on to a computer or portable terminal. Here the original data is recovered. A bar code works like a light when turned on in a dark room. You see the walls and furniture in the room by the light reflected from these items.
The scanning device contains a small sensory reading element. This sensor detects the light being reflected back from the bar code, and converts the light energy into electrical energy. The result is an electrical signal that can be converted into data. Scanners employ various technologies to “read” codes. The two most common are lasers and cameras. Scanners may be fixed position type or hand-held devices.
History of Barcodes
In 1948, a local food shop owner Philadelphia (Pennsylvania) requested Bernard Silver, a research student to devise a method of automatically reading product information during checkout. Bernard Silver joined together with fellow research student Joseph Woodland to work on a solution. After four years of hard work, Woodland and Silver developed a method of “article classification through the medium of identifying patterns” and got it patented on the 7 October 1952.
Thus began the system of barcodes. The first product to have a bar code was Wrigley’s Gum. Bar codes were first used commercially in 1966, but it was soon realized that there would have to be a common standard all over the world to derive maximum benefit.
The Universal Product Code (UPC) was the first bar code symbology to be widely adopted. This was on 3 April 1973. Foreign interest in UPC led to the adoption of the EAN (European Article Numbering) code format, similar to UPC, in December 1976.
Currently, the United States and Canada use UPC bar codes as their standard for retail labeling, whereas the rest of the world uses EAN. Numerous other methods of bar-coding have evolved ever since. Originally barcodes were, stored data in the widths and spacing of printed parallel lines, but nowadays they also come in patterns of dots, concentric circles, and hidden in images. Also today we have numeric-only barcodes, alphanumeric barcodes and 2-Dimensional barcodes.
Consider a barcode found on a loaf of bread which contains a 12-digit product number. When this number is scanned by the cashier, it’s transmitted to the store’s computer which finds the record associated with that item number in its database. The matching item record contains a description of the product, vendor name, price, quantity-on-hand, etc. The computer instantly does a “price lookup” and displays the price on the cash register (it also subtracts the quantity purchased from the quantity-on-hand.) This entire transaction is done instantly; think of how long it would take the cashier to key in a 12-digit number for every item you wanted to buy!
Barcodes are thus a time saving, cost effective and accurate means of handling and checking large numbers of consumer goods.
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History of Glass
Although known to man for ages, glass is a transparent beauty that fascinates us even today. How did man discover the process of making glass? How is glass shaped?
Have you ever wondered where glass comes from? Today, all the glass we see around us is manufactured in factories. We take glass for granted, but few people are aware of its origins.
History and origin
The precise origin of glass is not known. Narrations in historical documents however show that natural glass was discovered by man perhaps as early as the Stone Age. Manmade glass came into the picture much later.
According to the writings of the Roman historian Pliny (AD-23-79), Phoenician merchants who traded soda, undertook long voyages to carry on the trade. On their way they would spread out on seashores to prepare their meals, and lit fires on the sands. The problem was that on vast empty shores of the beach they could not find anything to support their cooking pots over the fire. Therefore they used lumps of soda.
One such time, as the fire grew stronger, streams of liquid started flowing around the fire. The soda had combined with the sands, which melted in the intense heat and formed a curious liquid. As the fires died, the liquid solidified to form a transparent material. This was glass.
The basic raw materials of glass, silica i.e. sand and soda, were thus discovered around 5000 B.C. Man now knew that glass is nothing but sand, melted and then cooled.
This may seem confusing because we have seen that when solids melt to form liquids, on cooling, they generally return to their original state, like wax. Not so in the case of sand. Sand molecules rearrange themselves in a new fashion once they are melted and cooled, giving us continuous transparent medium or glass.
These merchants spread this knowledge along the Mediterranean coast and a new craft, that of glass making, was born.
Glass as found in nature
In nature, glass was discovered perhaps during volcanic eruptions, when certain types of rocks melted and then, cooled and solidified very rapidly. This was presumably the first known form of glass. It was called ‘obsidian’ and was used to make cutting tools like spears knives etc. by the people of that age.
Other violent natural phenomena (associated with high temperatures) like lightning strikes into sand dunes, melted sand and produced glass. The glass from these sources was called ‘fulgerite’. Other names such as hyalopsite, Iceland agate, mountain mahogany and obsidianites were also prevalent.
These naturally occurring forms of glass are no longer of any significance.
In modern times
Today the art of glass making has flourished all over the world. The way glass is prepared transformed into various shapes is remarkable. When in the molten state it flows and then is quickly blown and moulded. So simple, yet so amazing!
Innovations in style and utility of glass continue to this day. From dÃ©cor items to microwave safe dishesâ€¦ the possibilities are innumerable. The duality in its nature gives it a kind of mesmerizing charm; it could be opaque or transparent, clear or colored and strong but delicate.
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History of Salt
For most of us today salt is just another condiment. But historically, the innocuous looking white granular substance we know today as “salt” has been essential to life in many ways.
Chemically, salt is a mineral called “Sodium Chloride” (NaCl). Commonly called edible salt, table salt or just salt, it is one of a very few rocks commonly eaten by humans. There are different forms of edible salt: unrefined salt, refined salt, table salt or iodized salt. Salt is a crystalline solid, white in color, obtained from seawater or rock deposits. Sea salt comes in fine or larger crystals. As found in nature, it includes not only sodium chloride, but also other vital trace minerals. Salt flavor is one of the basic tastes.
Salt is essential for life and for good health. The sodium it contains helps maintain the fluid in our blood cells and transmit electrical impulses between our brain, nerves and muscles. Iodized table salt has significantly reduced disorders of iodine deficiency in countries where it is used. Iodine is important to prevent the insufficient production of thyroid hormones (hypothyroidism), which can cause goiter, cretinism and myxedema. Over consumption however, can also cause health problems, including high blood pressure.
History of Salt
Salt was in general use long before history, as we know it, began to be recorded. A Chinese treatise on pharmacology- Peng-Tzao-Kan-Mu- dating some 2,700 years B.C. is probably the earliest known records. This work mentions 40 kinds of salt, including descriptions of two methods of extracting salt and putting it in usable form that are amazingly similar to processes used today.
The preservative ability of salt is in a way the foundation of civilization. It eliminated dependency of man on the seasonal availability of food, allowed travel over long distances, and was a vital food additive.
However, because salt in the ancient times was difficult to obtain, it became a highly valued trade item throughout history. Until the 1900s, salt was one of the prime movers of national economies and wars. Realizing that everyone needed to consume salt, governments tried to create salt monopoly. Salt was often taxed; research has discovered this practice to have existed as early as the 20th century BC in China.
In ancient times Roman soldiers were paid their salaries in the form of salt. The word soldier comes from the Roman word saldare. It means to give salt. The Latin word salarium too means salt money. From the Latin “sal,” for example, come such other derived words as “sauce” and “sausage.”
Salt was of crucial importance economically. Interesting anecdotes from history make us realize this.
In ancient Greece, a system of trade involved the exchange of salt for slaves which gave rise to the expression, “not worth his salt.” In India “aapka namak khaya hai” is a phrase indicating one’s loyalty.
In the Mali Empire, merchants in 12th century Timbuktu valued salt enough to buy it for its weight in gold. The Venetian traveler Marco Polo who journeyed to China noticed that the people of Tibet used packets of salt as money. These packets bore the seal of the powerful Mongol ruler Kublai Khan, who then ruled China.
Under the rule of the first great empire in India of the Mauryas more than 2000 years ago, salt could be produced only by the ruler. Not only that, those who sold salt had to pay four different taxes. And those who bought salt had to pay two taxes on its purchase.
Tribes often exchanged their goods for salt from the people living in towns. It was an important trading commodity carried by explorers.
The manufacture and use of salt is one of the oldest chemical industries. Today, most refined salt is prepared from rock salt: mineral deposits high in edible salt. These rock salt deposits were formed by the evaporation of ancient salt lakes. These deposits may be mined conventionally or through the injection of water. Injected water dissolves the salt, and the brine solution can be pumped to the surface where the salt is collected. It is then purified according to need.
Only about 7% of refined salt is used as a food additive. The majority is used for industrial purposes like manufacturing pulp and paper, setting dyes in textiles and fabric, producing soaps and detergents and de-icing roads, and has great commercial value. In India, seawater is the main source of salt. Salt is also made from several salt lakes such as the Sambar Lake in Rajasthan, Chilka Lake in Orissa; salt springs in the Rann of Kutch, the Manekudi Lake in Kerala and the Vedaranyam swamp in Tamil Nadu.
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Chocolate through the years
The story of chocolate began with the discovery of America. Till 1492, world knew nothing at all about the delicious and stimulating flavour that has today become the favourite of millions. You guessed it; we are talking about chocolates.
Spain was the first to get the whiff of it. The court of King Ferdinand and Queen Isabella had their first tryst with the principal ingredient of chocolate when Columbus returned triumphantly from America and laid before the Spanish throne a treasure trove of strange and wonderful things. Among these were a few dark brown beans that looked most unpromising. They were cocoa beans, the source of all chocolates. The King and Queen did not realize the potential of these modest-looking beans and it fell on Hernando Cortez, the great Spanish explorer, to exploit the edible possibilities of these beans.
On his conquest of Mexico, Cortez found that the Aztec Indians were already using cocoa beans to prepare a royal drink called, “Chocolatl”, meaning warm liquid. In 1519, Emperor Montezuma, who reportedly drank 50 portions daily, served Chocolatl to his Spanish guests in great golden goblets.
However, Montezuma’s Chocolatl was too bitter for the Spanish palette. To make the concoction more agreeable to Europeans, Cortez and his countrymen conceived the idea of sweetening it with cane sugar. He took the new improved upon Chocolatl back to Spain. The sweetened version found favour with the Spaniards; the drink underwent further changes with newly discovered spices such as cinnamon and vanilla. It was thought that the drink would taste better if served hot and sure enough it gained universal acceptance.
This new drink quickly won loyalists, especially among the Spanish upper classes.During olden days beans of cocoa were used as currency in Mexico and only the rich could afford to literally drink up their wealth in chocolate beverages. Spain wisely proceeded to plant cocoa in its overseas colonies mainly in Venezuela and Jamaica, which gave birth to a very profitable business. Remarkably enough, the Spaniards succeeded in keeping the art of the cocoa industry a secret from the rest of the Europe for nearly a hundred years.
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Rain and Floods
How does rain form?
Water droplets form from warm air. As the warm air rises in the sky it cools. Water vapor (invisible water in the air) always exists in our air. Warm air holds quite a bit of water. For example, in the summer it is usually very humid. When enough of these droplets collect together, we see them as clouds. If the clouds are big enough and have enough water droplets, the droplets bang together and form even bigger drops. When the drops get heavy, they fall because of gravity, and you see and feel rain.
What causes rain?
When clouds develop or rain occurs, something is making the air rise. Several things can make this happen. Mountains, low-pressure areas, cold fronts, and even the jet stream.
How big are raindrops?
Raindrops are much smaller than we think! They are actually smaller than a centimeter. Raindrops range from 1/100 inch (.0254 centimeter) to 1/4 inch (.635 centimeter) in diameter.
How fast do raindrops fall?
Not including wind-driven rain, raindrops fall between 7 and 18 miles per hour (3 and 8 meters per second) in still air. The range in speed depends on the the size of the raindrop. Air friction breaks up raindrops when they exceed 18 miles per hour.
What is a flood?
A flood results from days of heavy rain and/or melting snows, when rivers rise and go over their banks.
What is a flash flood?
A flash flood is sudden flooding that occurs when floodwaters rise rapidly with no warning within several hours of an intense rain. They often occur after intense rainfall from slow moving thunderstorms. In narrow canyons and valleys, floodwaters flow faster than on flatter ground and can be quite destructive.
Do flash floods hurt people?
Flash floods are the #1 weather-related killer in the U.S. Nearly 80% of flash flood deaths are auto related. Know beforehand if your area is a flood risk.
How much water is needed for your car to float away?
A mere 2 feet of water can float a large vehicle or even a bus. This is why you should never drive through flooded roads. Just 6 inches of rapidly moving flood water can knock a person down.
What is radar?
Radar is an electronic instrument, which determines the direction and distance of objects that reflect radio energy back to the radar site. It stands for Radio Detection and Ranging. This is what meteorologists use to see rain or snow.
What is Doppler Radar?
Doppler Radar detects precipitation intensity, wind direction and speed, and provides estimates of hail size and rainfall amounts. Doppler Radar gives forecasters the capability of providing early detection of severe thunderstorms that may bring strong damaging winds, large hail, heavy rain, and possibly tornadoes. Combined with satellites, radar gives forecasters the ultimate tools to provide accurate forecasts and advanced severe weather warnings.
How does Doppler Radar work?
Doppler Radar gets its name from the Doppler Effect. Have you ever listened to a train whistle as it was coming toward you? You probably noticed that the pitch of the whistle changed as the train passed you and moved away. This change in the frequency of sound is called the Doppler Effect. Doppler Radar measures the changes in the frequency of the signal it receives to determine the wind.
What is NEXRAD Radar?
The National Weather Service has installed a new type of Doppler Radar called NEXRAD Radar. NEXRAD stands for Next Generation Radar. This radar produces many different views of storms and rain that allows meteorologists to determine if a storm could be severe.
RainKnow the LingoRain
FLOOD WATCH – means that an overflow of water from a river is possible for your area.
FLASH FLOOD WATCH – means that flash flooding is possible in or close to the watch area. Flash Flood Watches can be put into effect for as long as 12 hours, while heavy rains move into and across the area.
FLOOD WARNING – means flooding conditions are actually occurring in the warning area.
FLASH FLOOD WARNING – means that flash flooding is actually occurring in the warning area. A warning can also be issued as a result of torrential rains, a dam failure or snow thaw.
Click Here to see if there are any active warnings in your area.
RainFlood Safety TipsRain
BEFORE A FLOOD: Have a disaster plan and prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food, can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water.
DURING A FLOOD: Move to a safe area quickly. Move to higher ground, like the highest floor of your home. Avoid areas subject to sudden flooding like low spots and canyons. Avoid already flooded areas. If a flowing stream of water is above your ankles stop, turn around and go the other way. Do not attempt to drive through a flooded road. The depth of the water is not obvious and the road may be washed away. If your car stalls, leave it and seek higher ground. Rapidly rising water may engulf the car, pick it up and sweep it away. Kids should never play around high water, storm drains or viaducts. Be cautious at night, because its harder to see flood dangers. If told to evacuate, do so immediately.
AFTER THE FLOOD: Always, boil drinking water. Electrical equipment should be checked and dried before used.
Lesson Plan: Here is a great lesson plan on learning about precipitation. In this activity, kids will use a weather map to answer questions about precipitation falling across the country. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.
Rain Experiment: Here is a great experiment on making rain. In this experiment, kids learn about condensation.
Rain Experiment: Here is an experiment that lets kids see what’s in the rain. It shows kids that there are particles in the air and when it rains they get to see them up close.
Rain Gauge Experiment: Here is an experiment that allows a kids to make their very own rain gauge.
Raindrop Experiment: Here is an experiment that allows you to see a raindrop. In this experiment, kids will preserve raindrops, so they can measure to see how big they really are.
Watercycle Experiment: Here is an experiment that teaches kids about our water cycle. This experiment shows what happens to the water in our creeks, streams, rivers, lakes and oceans.
The Doppler Effect Experiment: Here is an experiment that teaches kids what the Doppler Effect is. They can learn how the Doppler Effect works and why Doppler Radar is such as important tool in weather forecasting.
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What does our tri-colour stand for?
Like our country, our national flag also has a history. Let us salute the flag.
Our tri-colour flag was born on July 22, 1947 in the Constituent Assembly, a few days before the country gained Independence. Our flag has three stripes of equal width, the top being saffron (kesari), followed by white and then green at the bottom. In the centre of the white band is a navy blue wheel with 24 spokes (Dharma Chakra).
The saffron stripe signifies courage, sacrifice and the spirit of renunciation. The white stripe signifies purity and truth. The green stripe stands for faith and fertility. The Chakra denotes continual progress of the country. Its blue colour connotes the boundless sky and fathomless sea. As is obvious, the founding fathers of India wanted limitless growth of the nation.
A few facts to note
The national song in the honour of the flag was composed in 1924 by freedom fighter Shyamlal Gupta.
Code of conduct:
It is the duty of every Indian citizen to know the code of conduct related to the national flag. It is his or her fundamental duty to display the flag in the correct stately manner. An incorrect display of the tri-colour is a punishable offence. A damaged or disheveled flag should not be displayed. No other flag should be placed higher than the tricolour. The tri-colour must not be used or stored in such a manner as may damage or soil it. Lettering of any kind should not be superimposed on the tri-colour.
Special occasions calling for display of the flag:
From the commencement to the finale of the Republic Day celebrations.
National week ( April 6 to April 13 ) in the memory of the people who lost their lives in the massacre of Jallianwala Bagh in 1919.
Independence Day ( August 15)
Mahatma Gandhi’s birth anniversary (October 2)
Any other day of national rejoicing as may be specified by the Government of India.
The word flag , which is of German origin, signifies a piece of cloth, bunting or a similar material displaying the insignia of a community, an armed force, an office or an individual.
In ancient India, flags had great significance right from the Indus Valley Civilization. The ancient flags were often triangular and unicolour. The flags belonged to a king, his kingdom and his army. But in modern times, a national flag does not belong to an individual person, but a whole nation. It stands for the nation’s aspirations, hopes and achievements.
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The Postal System
How does mail reach from one place to another?
Have you ever thought how a letter travels thousands of miles before reaching its final destination? This journey covered by a letter is extremely fascinating .So read on to know more about the process through which we receive a letter sent to us.
Let us read about the Postal system in our country by taking a look at various details of the Post office.
Ancient postal system
In ancient times, letters were sent through pigeons. The pigeon post was the earliest known form of sending messages through long distances. Can you believe that these pigeons were not the ordinary ones? They were called homecoming pigeons and were specially trained to deliver letters. A small metal box was attached to a pigeon’s leg and letters were put into it. The pigeons then found their way back to their homes. Once they reached, people helped them in taking out the letters.
How a letter travels great distances always fascinates us!
Try this yourself. Put a letter in the letter box and see how it is delivered from one place to another. It is collected by the postman and taken to the post office of your area. From here it is sent by train, road or air to the destined location of your letter. The postman is indeed our real friend. He faithfully delivers our letters, telegrams, money orders and parcels in all kind of weather conditions. In India we have letter boxes of different colours for local, interstate and international destinations.
Letters are written on postcards, inland covers, stamped envelopes and aerogrammes.
Postcards are issued by the post office; they can be used to write small messages as they don’t have much space to write on it, they are cheaper than envelopes and inland letters.
Inland covers are used to write long letters as they have a large amount of space and have stamps on them.
Envelopes are used for writing even longer letters and they need stamps to be pasted. One can make their own envelopes also.
Stamps should be pasted on the envelopes as we have to pay for using the services of the postal system.
PIN is an acronym which stands for postal index number. We should always write the correct postal address and pin code on our letters to help the postman deliver them at the right place.
Messages are sent even faster through telegraph system. If you want to send a short message quickly, you give it to the telegraph office with the address you want the telegram to be sent. It is send by a special telegraphic method to reach in a few hours
These days post offices have another facility where important letters and parcels are sent by speed post or by courier.
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The digestive process – what you eat and where it goes?
Have you ever thought about how the meals you eat provide energy?
It’s lunch break in school. You are sitting with your friends and enjoying the tiffin packed by your mom. A few idlis, chicken sandwiches or fruits – by the time you finish these goodies and head for your next class, you completely forget about the sumptuous meal. But do you realize what is happening with the food that is still lying in your stomach? You can visualise it like a science experiment in a chemical laboratory.
Your body is a marvellous machine far better than any invented by man and it can perform many important functions. But it also needs energy to survive and to do work. The oxygen you breathe in helps to ‘burn’ the food in order to give energy. The food you eat cannot be used by your body in that form. It has to be changed into a simpler form. This is done by a very special system called digestive system and the process is called digestion. One cannot get nutrients without it to remain healthy and grow properly.
How does the food get digested in our body? Do you know that the food which we eat goes through a number of processes before getting digested? How does a piece of bread, an apple or a glass of milk can give you energy? Have you thought about it?
It is interesting to know that the process of digestion begins in the mouth from the moment you take the first bite – in fact even before that! If some tempting dish is cooked in your house, just the aroma of it makes you feel hungry and you say, “It makes my mouth water!”. This ‘water’ is nothing but saliva, a watery fluid that is secreted by the salivary glands. It consists of chemicals called enzymes that mix with the food you eat and help in digesting it.
To learn more, do this activity in your mouth itself. Put a small piece of bread or chapatti and put it in your mouth, chew it for sometime but do not swallow. After 2 minutes, what do you feel? Do you get a sweet taste in the mouth?
When you chew the food it gets broken into small pieces by your teeth which help in cutting and grinding. The role of tongue is to mix saliva while food is being chewed and help in swallowing. Food then enters into a tube called food pipe, also known as oesophagus which connects the throat and the stomach. The stomach is like a mixer which churns and mashes the food to convert into a semi solid paste. Here it also mixes with ‘gastric juices’ secreted by the stomach walls that help in further breaking down the tiny bits of the food you ate. Some part of it is digested and the remaining passes to the small intestine.
The small intestine is the main region for absorption of digested food. Its inner surface has many finger-like projections which offer a large area that aid in the absorption of food. Juices secreted from liver and pancreas help in the digestion process. Undigested part passes to the large intestine. The large intestine absorbs water and the undigested food moves for disposal through rectum. This completes the digestion of food.
So kids, to keep healthy and fit, you must follow good eating habits. Help your digestive system by eating food rich in fibres like whole grains, proteins, fruits and green vegetables. If you have not chewed your food properly your stomach has to do that much extra work and gets overloaded – you suffer indigestion. Similarly overeating does not leave space for the stomach to do its expansion and contraction, again leading to indigestion. Always eat smaller quantities, at regular intervals and chew the food well as that helps in digestion. Do not run or do heavy exercise just after eating. Brush your teeth twice a day and always rinse your mouth with water after you eat.
Did you know?
The body produces about one litre of saliva a day and 95% of saliva is water.
Bacteria in the mouth break down sugars into acids and cause tooth decay.
The stomach can stretch to hold 2 to 3 litres of fluid.
The gastric glands produce about 2 litres of acidic fluid daily.
The small intestine is 285cms and the large intestine is 150 cm long.
The liver is the largest organ in the body. It produces bile juice which helps in digesting fats.
Next time when you sit for lunch or dinner, you will have all the knowledge of how your meals are digested.
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Did you know who was the first Indian female graduate?
Girls often surpass boys in school examinations. They also excel in the field of sports and performing arts. But, here we tell you about a period in the history of pre-Independent India when girls were not even allowed inside schools and colleges.
Parents in India did not accept the idea of sending their female children to schools. In 1848, when a girls’ school was founded in Mumbai, at the instance of veteran leader Dadabhai Navroji, parents agreed to send their girls only on one condition. The condition was that not a single English word would be taught to them. Parents felt that Western education will spoil their girls. The school had no other go but to agree to the condition. However, the authorities in the school introduced the English subject very secretly. When this fact came to be known to a Gujarati newspaper called `Chabuk’, the paper warned that “English-knowing girls will make their husbands live in hell.” Of course, the warning did not stop all girls from going to school. The clock of progress could not be reversed. However, it is surprising to know that girls’ education was limited to the sixth standard initially. College and university education was out of question.
The Universities of Calcutta, Bombay and Madras were founded in 1857. Yet, for the first 18 years, no girl student was enrolled. It was only in 1875, that one Parsi gentleman Sorabjee Kharsetjee inquired if his daughter could appear for the matriculation examination conducted by the University of Bombay. His request was not accepted. As luck would have it, a girl named Chandramukhi Basu applied for the matriculation exam in the same year at University of Calcutta. She was also denied permission.
It was in 1877 that Calcutta University first opened the doors for girl students, and Bombay University followed suit in 1883. Thus the gates of higher education were thrown open for women. In 1883, Chandramukhi Basu and Kadambini Basu of Calcutta University became the first women graduates in India. And Cornelia Sorabjee was the first woman graduate from University of Bombay. While these facts surprise us now, they speak of the past times and conventions.
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Ice and snow are both frozen states of water. But while ice is transparent, snow is absolutely white. Why is this? Read on.
Much of the fascination about snow is because of its milky white color. The sense of beauty and purity exuded by the snow layered terrains is mesmerizing. The term ‘snowhite’ is used to describe incomparable whiteness. Most people love the snow for the way it looks –white and serene.
Isn’t it interesting to note that the ice in your refrigerator is transparent while snow is white, although both ice and snow are solid states of water? Snow is just a bunch of ice crystals stuck together. So where does it get its distinctive color from?
Visible light or white light is made up of many different colors of light. Different objects have different colors because they absorb some colors and reflect others. Our eyes receive the reflected colors and the object appears to be of that particular color. Such objects are called opaque.
Why is ice transparent?
Transparent objects allow most of the light falling on them to pass through. Very little of the light that falls on them is absorbed. Some objects change the direction of the rays of light that fall on them. Such objects are called translucent. The ice in your fridge is not transparent but is actually translucent. This means that it does not allow the light to pass through a straight path. So light exits from a block of ice in a different direction than it enters it, thus making the ice appear translucent.
What is snow?
Snowflakes are formed when water vapor in the air suddenly freezes without first converting into liquid. The air currents keep on tossing these crystals in the atmosphere. This makes them collect into groups and float down to earth as snowflakes. Snow is therefore a whole bunch of individual ice crystals arranged together. On close observation it has been seen that snow is a six-rayed ice crystal of delicate quality.
What makes it white?
When a ray of light enters a layer of snow, it goes through an ice crystal on the top, which changes its direction slightly and sends it on to a new ice crystal, which does the same thing. Basically, all the crystals bounce the light all around so that it comes right back out of the snow pile. The same thing happens to all the different colors of the light rays that fall on it, so all colors of light are bounced back out. These colors combined in equal measure give us white, so this is the color we see in snow. In short, we can say that it is the reflection of light from the surfaces of the ice crystals that make the snow look white.
Did you know?
The sun is powerless to melt clean snow.
We have seen how snow reflects the light that falls on it. In fact, newly formed snow reflects about 90 per cent of the sunlight that falls upon it. This is the reason sun cannot melt clean snow. When snow does melt, it is not because of the sunlight but because of the warm air around, usually from the sea.
Interestingly enough, after snow becomes ice, the sun is still not very effective in melting it. Now a different problem arises because of the transparency of ice to light. The sunlight passes through it very quickly. It does not stay in the layers of ice long enough to get absorbed and thus raise the temperature of the ice and melt it. So when the ice is very cold and the layers very thick, the whole summer passes before any melting occurs. This is what happens in the Antarctic region.
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