North and South Pole - areas with more differences than similarities

North and South Pole areas for most people are real secret. Most people have a vague idea on these areas and imagine them as areas very similar to each other.
It is strange that between the Antarctic areas (South Pole) and Arctic areas (areas of the North Pole) there are more differences than similarities!
The area of the South Pole is mainly composed of the continent called Antarctica. This continent covered with snow and ice, has an area larger than Europe. In contrast, the North Pole area consists of the Arctic Ocean, surrounded by the shores of North America, Europe and Asia.
Other big difference is that the man, animals and plants gradually migrated northward in the North Pole area, adapting to the polar environment, but on the area of the South Pole, which is separated with hundreds of kilometers of ocean from all continents except South America, there are no land animals or people.
Plant life is there so poor that there only grow lichens, algae, grasses and some other plants. Penguins have a very nice life in this area, because here they have no natural enemies to fight with.
Arctic (orthographic projection)

And what is the climate?

In the Antarctic there is low temperature, even in summer, and in winter the biggest blizzard in the world.
In the area of the North Pole from the surrounding water there are rising air currents which keep the temperature is a little higher.
But in Antarctica, which is mainly covered by vast ice cover, a huge mass of cold high pressure air are created, so the climate is much sharper than the climate in the North Pole.
Even during the summer months the average temperature in Antarctica is below the frozing temperature of water!
From time to time, during some summer days, the temperature is known to climb to about 4 degrees above zero.
The winter average temperature at the South Pole ranges from – 20 C (-4 F) to -35 C (-31 F)!
In Antarctica the lowest ever recorded temperature was - 88 ° C (-126,4 F) !

Why do Seasons Change - What Causes the Change in Seasons?

Why do Seasons Change - What Causes the Change in Seasons?

People since ancient times considered the change of seasons.

Why is it hot in summer and cold in winter?

Why the days get longer in the spring?

Why during the winter the nights are longer?

We all know that the Earth revolves around the sun, and at the same time around its axis.
If the Earth's axis (the imaginary line that passes through the North and South Pole) was at 90 degrees to the Earth's orbit around the sun, than we would have no distinct seasons, and all the days of the year would have the same length.
But the Earth's axis is slightly tilted and this is because on the Earth influence various forces.
One is the attraction toward the sun, the other is attraction of the moon, and the third is the Earth’s movement around its axis.
Due to the action of these forces, the Earth revolves around the sun in an inclined position. The Earth is always throughout the year in this position, so that the Earth's axis always lies in the same direction - toward the North Star.
This means that the North Pole one part of the year faces the Sun, and the second part of the year away from the Sun. Because of this tilt, the sun's rays fall directly on the Earth, sometimes north of the Equator, sometimes on the Equator, and sometimes south of the Equator. The angle in which the sun rays fall on Earth is in strict correlation with the different seasons in different parts of the world.
When the northern hemisphere faces the sun, in the countries north of the Equator is summer, and in the countries south of the Equator winter.
When the sun's rays fall vertically to the southern hemisphere, it is summer there, and in the northern hemisphere winter.
The year has two days when day and night are equal around the world.
These are the autumn equinox on 23 September and the spring equinox on 21 March.

The equator - What is the Equator?

The Equator is very well marked on each map or globe, so for some people it is hard to believe that it doesn’t exist.
The Equator is only one imaginary line, which we can always cross and not to know that we’ve crossed it.
That’s why the sailors celebrate every passing of the Equator with appropriate crossing ceremonies.

What is the Equator?

The Equator separates the Earth to northern and southern hemispheres. It is an imaginary line that goes around the circle the Earth in the middle, between the North and South Pole.
Other imaginary lines that make a circle around the Earth parallel to the Equator are called "parallels". The Equator is marked with zero, and the lines above and below it, signify north and south latitude, which are used to make it easier to locate a point on the Earth's surface.
As we know the Earth in the maps is divided into several areas. Starting from the top, or from the north, we have the arctic regions, tropical regions and the south temperate Antarctic area.
Tropical or equatorial region extends from the Equator to the north and the south to 23.5 degrees north and 23.5 degrees south latitude. In these areas the sun's rays fall vertically, and therefore there is always warm.
As we know, the Earth's axis is inclined relative to its orbit around the Sun. Therefore, the Equator is tilted in relation to this trajectory, for exactly 23.5 degrees. As the Earth revolves around the sun, the sun's rays because of this inclination sometimes fall vertically on the areas north of the Equator, sometimes on the Equator, and sometimes south of it. However, the sun can never be directly overhead at places outside 23.5 degrees north and south latitude.
This explains why the area Equator is only part of the Earth where the sun's rays fall vertically. Since this is happening throughout the year, it is clear why on the Equator is always so hot!

Moving continents - Are the continents still moving?

Moving continents - Are the continents still moving?

If you look at a map of the world and the shapes of Africa and South America, you will notice that they seem to fit together.
If you make a jigsaw puzzle of the two shapes, you will see that this is true.
Early in the 20th century, a German scientist called Alfred Wegener studied fossils in rocks from Africa and South America. Fossils are imprints or remains of plants or animals usually found in rocks. He found that the fossils on both continents were the remains of the same animals and plants.
He introduced the theory that mountains in different countries might once have been joined together.
The Cape Mountains in South Africa, for example, could have once been joined to mountains south of Buenos Aires, in Argentina.
Wegener believed that, over millions of years, the continents had gradually moved away from each other.
Continents are still moving today.
Scientists call this movement the continental drift.

Why are the continents moving?

The earth’s crust is made up of a number of enormous separate pieces, called tectonic plates. These plates fit together, like the pieces of a puzzle.
Tectonic plates are all moving, very slowly, in different directions.
Scientists are not sure why these huge, curved sheets of rock move. These solid plates are floating on the mantle, the thick layer of solid rock that also contains hot, liquid rocks moving underneath the earth's crust.

How fast are the tectonic plates moving?

Tectonic plates move from less than one inch (2.5 centimeters) to eight inches (20 centimeters) a year.

How were the continents formed?

As the plates move, they carry the continents and ocean floor with them. Tectonic plates have been moving for billions of years.  More than two hundred million years ago the earth’s dry land was all bunched together, forming one gigantic continent. Slowly, as the plates moved, the one huge continent broke into two continents.
And, as the plates continued to move, both of these continents broke up to form the seven continents we know today.
As the plates keep moving, the continents and seas are still changing shape. Millions years from now, the continents will be even farther apart than they are now.
The ocean will become wider and Australia may move up and push against Southeast Asia, becoming part of it.

How was the Earth Formed - for Kids

Why the earth is round in shape?

Why does the earth spin?

Why does the earth rotate around the sun?

The answers to these questions are connected to the story of “How was the Earth Formed”.
It all started billions of years ago, with a giant, spinning cloud in space.
There are many such clouds in space right now. They are made up of chemicals in the form of gas and dust.
Some of these clouds are turning into new stars, the same way as five billion years ago, our sun and its planets were formed.
These clouds are hundreds of millions of miles wide!

The force of gravitation (the same force is keeping us on the ground) pulled the gas and dust particles into a shape of a huge, flat wheel, which spins around.
Gravitation slowly pulls the cloud together. Most of the gas is collected in the middle of the cloud and forms a lump that grows bigger and bigger.
As the lump gets bigger, its gravity becomes stronger and it pulls more gas into itself.
Because gravity pulls equally from all directions, the lump is squeezed into a shape of a round ball.
After a long period of time, there is a gigantic ball of gas in the middle of the wheel-shaped cloud.
This is the beginning of new sun.

In the rest of the cloud, other balls are also forming as gravity pulls bits of dust and gas together. After certain period of time (millions of years), most of the cloud is used up and there are only balls of gas and dust, spinning around the sun.
Planets are spinning around the sun because the cloud they were made from also had been spinning.
This is the way how the Planet earth and all other planets in our solar system were created, and how as you read this, other planets and solar systems are formed.

And this is why the earth rotates around the sun.

But how did the earth from spinning ball of dust and gas became a ball of rock and metal?

As the earth’s gravity pulled more dust and gas in, everything was squeezed together tighter and tighter!
This made the ball grow hotter and hotter and it became so hot that the bits of dust in it, which were mostly rock and metal dust, melted together.
The earth became a glowing ball.
But on the outside of the earth couldn’t stay hot.
So the earth began to cool down, and when melted rock and metal cools, it gets hard.
This way the earth became a ball of hard rock and metal, as it is today.
The earth still hasn’t cooled off and the middle is still fiercely hot, since part of the inside is still melted.

How does a light bulb work - for kids?

How does a light bulb work - for kids?

Have you ever looked closely at an ordinary electric light bulb?
Hold it carefully while you do so.
Inside, you may see wire "legs" holding up a thinner wire arranged in a coil.
When a light bulb is switched on, electricity flows along the thin wire and makes it glow.
Why does it glow white, and not red like the wire in an electric heater?
Why doesn't the thin wire quickly burn out?
Many bulbs are filled mostly with argon gas. Because argon is inert, or chemically inactive, it allows the wire to glow brightly without burning.
If the bulbs were filled with air or oxygen, the wire would be destroyed by burning.
The wire glows white because it is so hot—over 4500°F (2482°C). And it doesn't melt because it's made of a metal called tungsten, which melts only at extremely high temperatures.

Gases in bulbs

Sometimes the gas inside a lamp produces a colored light.
Different gases glow in different colors. Street lights that shine yellow contain sodium as a gas. Neon gas glows orange-red, and krypton makes a greenish-yellow light. In fact, different mixtures of gases in special lamps can produce many different colors.
In these lights, the electricity doesn't flow along a wire. It flows through the gas inside a thin, glass tube, making the gas glow. In a city at night, you can see lamps lighting up advertisements. These often flash on and off. Neon mixed with other gases gives them their different colors.
Halogen light is especially useful because it can be seen through thick fog. So it is often used in the warning lights at airports.
Xenon can be seen from long distances. That's why the high-powered electric lamps used in some lighthouses may contain xenon. Xenon is helpful to photographers, too. It is the gas used in the tubes of electronic flash units.

How is natural gas produced? - natural gas for kids

How is natural gas produced?- natural gas for kids

The most important gas that we use as a source of energy is natural gas.
We don't have to make this. It is found in deposits under the ground, usually near deposits of oil.
Natural gas is a mixture of several gases, including butane and propane.
Most of it is methane.
Natural gas comes from vegetation that decomposed millions of years ago.
Natural gas is used to provide heat for industry, and also for cooking and heating in our homes.
It comes to our homes through pipes laid under the streets of towns and cities and across the countryside.
In some places, natural gas is piped direct from the gas production platforms, where it has been pumped up from beneath the seabed or from deep underground.
In other places, it is shipped as a liquid in refrigerated tankers. It is pumped from the ships into storage tanks at the docks.

Adding a smell

Unlike gas made in gasworks, natural gas doesn't have an odor.
This means that we would not be able to tell if a pipe were leaking gas into the air. Because natural gas is mostly methane, it can easily explode when mixed with oxygen.
So a smell is added to the gas before it reaches us to help us detect any possible leaks.
The world's supply of natural gas, formed millions of years ago, won't last forever.
Scientists cannot agree about how long supplies will last, but it could be as little as 75 years.
By then, methane might be available from sources such as sewage.
When bacteria break down sewage at the sewage treatment plant, methane is given off. This gas could be collected and stored as a fuel.

Gases and decay

One day, each plant and animal alive on this earth will die. If nothing happened to all these dead things, they would be left lying all over the earth.
But fortunately, when the cells of living things die, they quickly start to change, or decompose.
Most of the decomposing work is done by tiny living things called bacteria.
These break down the chemicals in dead plants and animals, and change them into simple substances, Some of these substances, such as nitrogen, return to the soil.
Nitrogen helps produce new growth in plants.
Fertilizers contain certain percentages of nitrogen, usually in combination with oxygen.

Gases from garbage

Some of the substances produced by decomposition are given off as gases.
Large amounts of household waste are dumped in huge garbage dumps in and around our cities and towns. As this garbage decomposes, it gives off different gases.
The main gases given off by rotting garbage are carbon dioxide, hydrogen, methane, nitrogen and oxygen.
As time goes by, the amount of each gas given off by the garbage alters. For instance, after about six months the two gases given off are oxygen and nitrogen.
But after five years the garbage gives off mostly carbon dioxide and methane.
The methane gas can be collected and used as a fuel.

Methane gas can cause great danger to miners. When miners are drilling into the rock surface, they sometimes break through into deposits of methane. The gas escapes, and if there is air present, a terrible explosion can take place. Sparks from electric switches or from friction between steel and rock can cause the inflammable methane to ignite. Mines now have very strict safety rules in order to prevent these explosions.

Traveling to Antarctica - Information about Antarctica

Traveling to Antarctica - Information about Antarctica

Antarctica is located around the South Pole. Antarctic continent is the fifth largest among the continents, with an area similar to the areas of United States and Europe together.
This area is the coldest part of the globe.
Antarctica is surrounded by the most turbulent seas in the world. There are blowing cold winds, frequent storms, little water sediment and winter is so strong that the whole of this area is almost completely deserted.
There is never enough solar heat in the country, which during the whole year is covered in snow.
The lowest temperature that was ever recorded in the world, was found just in Antarctica.
Due to the immense cold, in Antarctica the food doesn’t spoil, there is no mold, mildew or bacteria.

What lies beneath the ice cover?

It is not known exactly, because the Antarctic is not yet sufficiently researched. The researchers noted coal deposits and some minerals. It is possible there are other minerals, but it would be too difficult and too expensive to reach them so they remain intact.
There are the simplest forms of plant life - mosses, lichens, fungi and algae, which can be used as food. In this area only live birds and animals that can find food in the sea.
On the Antarctic often live some kinds of gulls, snow petrel and several species of penguins. Penguins live and bend their nest on the edge of the continent.
They have underdeveloped wings and can’t fly, but they are very good swimmers in the water. In the waters of Antarctica there are several species of seals and this area has many whales.

Where Is Antarctica located?

Antarctica is located around the South Pole.
Antarctic continent is the fifth largest among the continents, with an area similar to the areas of United States and Europe together.
This area is the coldest part of the globe. It is surrounded by the most turbulent seas in the world.

Map of Antarctica

Antarctica is located around the South Pole. Antarctic continent is the fifth largest among the continents, with an area similar to the areas of United States and Europe together.

Capital of Antarctica

Antarctica is the fifth largest continent with 98 percent of its surface covered by ice.
Antarctica has no permanent residents, cities, government and NO CAPITAL.
Several countries have their scientific research facilities on Antarctica.

Climate in Antarctica

Antarctica is the coldest continent on the Earth. The coldest natural temperature ever recorded on the planet was −128.6 °F (−89.2 °C) and it was recorded at the Vostok Russian Station located in Antarctica on 21. 07.1983.
Antarctica is considered a frozen desert with very little precipitation.
On average temperatures there reach a minimum of between −112 °F (−80 °C) and −130 °F  (−90 °C) during the winter and a maximum of 41 °F  (5 °C) - 59 °F  (15 °C) during summer.

Antarctic Animals

Do you know of a place where it is always cold? There are two places like this, at opposite ends of the earth. The Arctic is the area around the North Pole, and the Antarctic is the area around the South Pole.
It’s so cold around the poles that snow and ice cover both the land and the sea for most of the year. Animals that survive here have different ways of coping with the cold.
The female emperor penguin stays at sea during the winter. It never gets as cold there as on land.
But the male penguin stays on the land to incubate an egg laid by his mate before she went to sea. The male penguin holds the egg on his feet. He has a thick flap of feathered skin there to keep the egg warm.
When the chick hatches, the father bird feeds it a thick, rich liquid, much like the milk of mammals. He produces this liquid in his throat.
When the females return in the spring, all the penguins call loudly, recognizing their mate by their voice. The females then look after the young penguins, and the males go off to sea.

What is pollination - for kids

Pollination definition for kids

Have you ever noticed how pleasant many flowers smell?
They have attractive scents, as well as bright colors, in order to attract insects. Insects use the nectar made by flowers as food.
In the process of getting the food, the insects transfer pollen from flower to flower.
The process of seed formation begins with this transfer of pollen grains from one flower to the stigma of another flower of the same kind.
This transfer is called pollination.
The main insects which pollinate flowers are bees and butterflies.
These insects feed on the sweet, sugar liquid called nectar that is usually produced by special cells in the receptacle.

On its way to the nectar, the insect has to pass the flower's anthers, which are covered in pollen. Some of the pollen sticks to the insect's body and then brushes off onto the stigma of the next flower that the insect visits.
A thin tube grows from the pollen grain, down through the style, and into the ovule. A male cell, carried by this pollen tube, unites with an egg, and the ovule starts to develop into a fertile seed.

Wind pollinated flowers

Some flowering plants, such as grasses and hazel trees, don't have any nectar in their flowers to attract insects. These plants need the wind to pollinate them. The wind blows the pollen off the anthers of one flower and onto the sticky stigma of another flower.
The stigma of a wind-pollinated plant can be large and feathery, in order to catch the pollen more easily. It's the wind that takes the pollen from male cones to the ovules of female pine cones, too.

What are annual plants, biennial plants, perennial plants?

Some flowering plants, such as nasturtiums and giant sunflowers, grow and die in the same year.
We call these annuals.
Not all annuals are welcome in our gardens— many weeds are annuals!
Other plants take two years to grow.

We call these biennials.
Flowers such as foxgloves and vegetables such as carrots and parsnips are biennials. In their first year, biennial plants store up food. In their second year, they use the food, flower, and die.

Some plants, such as irises, madonna lilies, and begonias, go on growing and flowering for many years.
We call these perennials.

Germination of seeds for kids - What is germination?

Germination of seeds for kids - What is germination?

Have you ever tried to grow your own plants?
If you have, you may have started with seeds.
Plants have male and female parts.
In seed-bearing plants, the male reproductive cells, called sperm, are carried in tiny grains called pollen.
These cells are released into the ovary, the female part of the plant.
There, one of the sperm joins with a female reproductive cell, called an egg, to start a new plant.
This tiny new plant, called an embryo, is at first kept in a seed with its own store of food.
Seeds can be many different shapes and sizes but they all do the same job. They are scattered away from the parent plant.
The outer cover of each seed protects the embryo until the seed lands in a suitable place. When conditions are right, the seed takes up water and the new plant grows out of it.

This is called germination.

What do seeds need to germinate?

How do seeds germinate?

The name for the moment in which seeds start to grow is germination. Seeds come in many different shapes and sizes—big ones, small ones, round ones, flat ones, and thin ones.
No matter what they look like, each seed has a tough outer coat and enough stored food to start growing.
Some seeds can wait a long time before they germinate.
If you buy a packet of seeds and keep it dry, you can plant the seeds several years later and they will still grow into healthy plants. Some seeds of poppies and docks have stayed underground for many years before germinating into new plants!
When a seed germinates, one part grows upwards and one part grows downwards.
The part that grows upwards is called a shoot, and the part that grows downwards is called a root.
Seeds will not germinate until they receive three things— water, warmth and oxygen—all at the same time and in the correct amounts.

Roots And Shoots

Did you know that shoots grow upwards? Shoots grow toward the light, which they need in order to make their own food. Sunlight provides the energy that plants use to make the sugars and starches that are their food.
Did you know that roots grow downwards?
Roots fix plants firmly in the ground. Large trees, for example, have many big spreading roots to anchor them. Roots also absorb water and other nutrients to help plants grow.

Plants without Seeds, Spores

Some plants can reproduce themselves without using seeds or spores. Many of these plants have male and female parts, but they may not use them to make seeds or spores. Instead, new plants develop from special buds on the parent plant.
Tiny organisms called algae may be so small that each is made up of just one plant cell. This cell can split into two to make two separate algae. This splitting process is called binary fission.
Beach grass grows new plants from a network of long stems that spread sideways underground. This is very useful in sand dunes near the sea, because the stems anchor the plant in the ground and at the same time stop the wind from blowing all the sand away.
The part of the potato plant that we eat is called the tuber. Tubers are part of the stem that grows underground. If they are not dug up and eaten, the tubers will grow into new potato plants. Look closely at a potato and you'll see the small buds, called eyes, that grow into new plants.
Bryophyllum is called the good luck plant. Tiny new plants grow on the edges of its leaves. The new plants drop down to the ground, root themselves and start growing as separate plants.
Metatarsalgia definition - What is Metatarsalgia?

Metatarsalgia definition - What is Metatarsalgia?

Metatarsalgia definition - What is Metatarsalgia?

Metatarsalgia is defined as pain in the instep area.

What causes Metatarsalgia?

The most common Cause is a form of flatfoot in which the arch between the bases of the big and little toes is deformed and the heads of the metatarsal bones rest on the ground.
This pressure on the bones produces pain, causes the skin to thicken, and may eventually cause the toes to curl.
Metatarsalgla may also be caused by a stress fracture, which can occur after prolonged walking or running.

Metatarsalgia treatment

Rest of the injured foot and wearing a soft-soled shoe is usually the only treatment required.
Prolonged physiotherapy to strengthen the underlying muscles may be effective in patients under the age of 40 years.
But if the pain is severe, it may be necessary to wear a cast for about one month.

Mercury chemical element - facts about mercury element

Mercury chemical element - facts about mercury element

Mercury is a liquid, metallic element that is commonly used in thermometers and other measuring instruments.
Some mercury compounds are still used in antiseptics and eye ointments.

What is the chemical symbol for the element mercury?

The chemical symbol for the element mercury is:

Atomic Number: 80
Atomic Mass: 200.59 amu
Number of Protons/Electrons: 80
Number of Neutrons: 121

Who discovered the element mercury?

The element mercury was known since ancient times and it is unknown who discovered it first.
Its name originates from the planet Mercury

Is mercury poisonous?

Small amounts of liquid mercury, such as that found in a thermometer, are not especially dangerous, because the element if ingested is poorly absorbed by the gastrointestinal tract.
However, mercury compounds, known as mercury salts, and mercury vapor are toxic, particularly the vapor, which is very readily absorbed through the lungs.
It affects the brain very quickly and is retained in the kidneys, resulting in renal failure.

How do you get mercury poisoning?

Acute mercury    poisoning may result from accidental (or deliberate, in the case of suicide attempts)
ingestion of mercury salts.
Chronic mercury poisoning usually results from exposure to mercury in the workplace or ingestion of mercury from foods contaminated by industrial pollution or chemical treatment.
A pollution-related outbreak occurred in Minamata Bay, Japan where several hundred people suffered irreversible damage or death from eating contaminated fish.

Mercury poisoning symptoms

Acute mercury poisoning symptoms include:
  • diarrhea,
  • vomiting and
  • kidney failure.
Symptoms of chronic mercury poisoning include:
  • tremors albuminaria,
  • paralysis, and
  • mental disturbances.