Amazon Rainforest Facts - Interesting Facts about the Amazon Rainforest

  • The Amazon rainforest, located around the river Amazon, is the largest expanse of the world covered with dense tropical forests. 
  • The Amazon rainforest covers an area of more than 5, 5 million square kilometers, which is about 60 percent of the entire continent of South America.

  • Amazon rainforest spreads out in 9 countries, including Brazil, Bolivia, Ecuador, Colombia, Peru.
  • Intertwined with dense and high vegetation, impenetrable, the Amazon rainforest is still unexplored completely, and yet disappears from the face of the earth.
  • Into the inaccessible areas, where constant moisture and dusk rule, there are very few people, mostly Indians, who live by hunting, fishing , gathering fruit and rubber.
  • The average temperature in the Amazon ranges from 25 to 28 degrees Celsius (77 – 83 F).
  • There are no seasons, and drought days are rare.
  • Humidity is very high, about 50 percent during the day and at night is coming up to 100 percent.
  • The average annual rainfall ranges from 1500 to 4000 millimeters.
  • According to the latest census made by the naturalist, driven back 10 years and involving 88 institutions around the world, the rainforest is composed of about 390 billion trees, of which 16,000 various species, high between 30 and 60 meters .
  • It is believed that Amazon Rainforest is home to about 2.5 million insect species, at least 2,000 species of birds, over 250 species of mammals, 2,200 species of fish and over 378 specimens of reptiles.
  • According to the findings of the researchers, at an area of about 10 square kilometers can be found more than 1500 plant, 700 animal and 1,000 species of insects.
  • In one study it was shown that on an area of one square meter, were living as many as 50 species of ants.
  • However, these data, no matter how scientifically documented, are not completely reliable.
  • The situation in the Amazon rainforest changes daily.
  • Dense forest is cut down, marshy ground dried out and turned into arable land.
  • The destruction of rainforests in the past years increased by almost a third, according to data released by the government of Brazil .
  • As of July 2012 until July 2013 are destroyed total of 5,850 square kilometers of rainforest, which was an increase of 28 percent compared with the same time of the previous two years.
  • According to the mathematical model used in this study, Amazon has about 6,000 species of rare trees with less than 1,000 trees, which means that the International Union for Conservation of Nature should put them on the endangered species list.

Satellites For Kids - Artificial Satellites Information For Kids

How far can you throw a ball?

About 60 or 70 feet (18 or 21 meters)?

Why doesn't it travel any farther?

Gravity limits the distance.

When you throw a ball, it rises into the air, but the earth's gravity soon pulls it back to the ground.
To launch a spacecraft, we somehow have to overcome gravity.
How do we do this?
We do it by speed.
Think of yourself throwing the ball. If you throw the ball gently, it goes slowly, and it doesn't travel very far. But the harder you throw it, the faster it travels, and the farther it goes. You are starting to beat gravity by speed.

If you could throw the ball faster and faster, it would go farther and farther before it dropped back to the ground. Eventually, you could make it go so fast that its curve, as it fell, would be the same as the curve of the earth's surface. In other words, it would stay the same distance above the surface.
It would then be in orbit around the earth.

To launch your ball into orbit you would have to give it a speed of more than 12 times that of a rifle bullet!

The speed is over 17,000 miles (27,400 kilometers) an hour.

This is known as the orbital velocity.

If you wanted to send your ball to Mars or another planet, you would have to throw it even faster, at a speed of just over 24,800 miles (40,000 kilometers) an hour. Then it would escape earth's gravity completely.

This speed is called the escape velocity.

Equatorial orbits go around the equator. Polar orbits go over the poles. In a geostationary orbit, a satellite keeps pace with the earth's rotation and appears fixed in the sky.
Space scientists send their satellites into orbit at orbital velocity. Up in space, about 186 miles (300 kilometers) above the earth, a satellite circles around the earth in about one hour.

How does satellite stay circling up in space?
Why doesn't it soon slow down and fall back to earth?

The reason is that there is neither air nor anything else to cause friction, which would slow it down. So it circles round and round at the same speed.

When was the first satellite launched into space?

In 1957, the first artificial satellite was successfully launched into orbit around the earth.
Since then, more and more satellites have been launched into orbit.
These satellites are helpful to people in many different ways.
Communications satellites carry telephone calls and television programs between the earth's continents.
Weather satellites help people to make accurate weather forecasts.
Earth-survey satellites help people to make better maps and find where useful minerals are.
Astronomers use satellites to study the universe.

What are satellites made of?

Satellites are built of lightweight materials. They are not streamlined, nor smooth like airplanes.
Can you think why?
No matter what they are used for, most satellites have certain things in common. They carry a radio and several antennas.
Some of the antennas are shaped like dishes.
Satellites carry various measuring instruments and sometimes cameras.
The radio sends, or transmits, the information back to Earth.
On many satellites, there are large, flat parts that look like paddles. These are solar cell panels which capture the energy in sunlight and change it into electricity. The electricity powers the instruments and radio on board the satellite. Sometimes, the solar cells are fixed around the outside of the satellite.

Communications and tracking

Scientists use radio to send signals to satellites and receive information from them. Satellites whizz endlessly around the earth. But you cannot send signals to a satellite if it is on the opposite side of the earth, because the earth blocks the signals.

Tracking Satellites

Before scientists can communicate with a satellite, they must know where it is.
They must have a means of following, or tracking, it all the time.
Again, they do this by radio.
They use large dish antennas at tracking stations to listen for the satellite's signals. The antennas track the satellite's movement across the sky and exchange signals with it.
It is even more important for astronauts to keep in contact with the earth, so that the scientists on earth can check that everything is working properly.
The main communications center for manned trips in space is called Mission Control.
The most famous Mission Control center is in Houston, Texas.

Protons Neutrons and Electrons

What is a Proton?

Protons are positively charged (+1), quite the opposite, as the electric charge of electrons (-1).
The number of protons in the nucleus determines the total amount of positive charge in the atom.
In electrically neutral atom, the number of protons and electrons is equal, such that positive and negative charges are balanced to zero.
Proton is very small, but it is quite massive in comparison with other particles that make up matter. Mass of the proton is about 1840 times the mass of the electron.

What is a Neutron?

Neutrons are about the same size as protons, but slightly heavier.
Without the neutrons, the repulsion between the positively charged protons would cause the nucleus to apart.
Consider an element of helium, which consists of two protons in its nucleus.
If the core does not contain neutrons, it will be unstable due to the electrical repulsion between protons.
The nucleus of the element helium requires one or two neutrons to be stable.
Most atoms are stable and exist for a long period of time, but some of the atoms are unstable and spontaneously decompose and change or decay other atoms.
Unlike electrons, elementary particles, protons and neutrons are made up of other, smaller particles called quarks.
Physicists know of six different quarks. Neutrons and protons are made of quarks and down quarks-up of two of the six different types of quarks.
Fancy names quarks do not have anything to do with their properties, the names are simply labels to distinguish one from the other quark.

What is a Electron?

Electrons are tiny, negatively charged particles that form a cloud around the core of an atom. Each electron carries a single basic unit of negative electric charge, (marked  -1).

What is Measured in Amps?

Most electrical appliances have wires attached to them.
The wires carry an electric current around a complete pathway called an electric circuit.
Some appliances need more electric current than others before they will work.
The amount of electric current depends on how much electricity is flowing along the wires.
How can we measure the amount of electric current?
We could try counting the number of electrons that pass along the wire each second.
But this wouldn't be easy!
There are a huge number of electrons traveling along most electric wires.
About 3 million million million electrons flow through a flash bulb every second!

To make it easier, we measure the flow of electric current in amperes. 

The word ampere comes from the name of the French scientist Andre Ampere, who invented a way of measuring electric current.

We usually say amp instead of ampere. 

One amp is equal to about 6 million million million electrons every second. So a flashbulb would have a current of half an amp flowing through it.
That's much easier!
Scientists use a special measuring device called an ammeter to measure the electric current.
The ammeter is connected into an electric circuit so that the electrons flowing around the circuit also flow through the ammeter.

Vitreous Humor Definition - What is Vitreous Humor

There are two humors, the aqueous humor and the vitreous humor, both of which help to maintain the shape of the eyeball.
The aqueous humor is a transparent liquid that fills the region between the cornea at the front of the eye and the lens.
The vitreous humor is a transparent, jelly-like substance that occupies the region between the lens and the retina at the back of the eye.
Vitreous Humor Definition - What is Vitreous Humor

The vitreous humor is present from birth and remains virtually unchanged throughout an individual's life.

Vitreous humor disorders

Specks may occur in the vitreous humor caused by the degeneration of its cells with age. This is a normal occurrence.
The presence of specks does not noticeably impair vision.
Occasionally, a hemorrhage into the vitreous humor may occur, usually caused by an injury.
A hemorrhage may also occur in diabetes mellitus, arteriosclerosis, or retinitis. A hemorrhage may be serious and a physician should be consulted.

Aqueous Humor Definition - What is Aqueous Humor?

There are two humors in the eyes, the aqueous humor and the vitreous humor, both of which help to maintain the shape of the eyeball.
The aqueous humor is a transparent liquid that fills the region between the cornea at the front of the eye and the lens.
The vitreous humor is a transparent, jelly-like substance that occupies the region between the lens and the retina at the back of the eye.

How is the aqueous humor produced?

The aqueous humor is constantly secreted by the ciliary body around the lens, so there is a continuous flow of the humor from the lens area to the eye's front chamber.
The aqueous humor is kept at constant pressure by a compensating leakage in the angle between the outer rim of the iris and the back of the cornea.

Function of Aqueous Humor

The aqueous humor carries nutrients and facilitates the exchange of gases (oxygen and carbon dioxide) in the cornea and other tissues of the eyeball that have no blood supply.

Aqueous Humor Disorders

Several disorders may affect the aqueous humor. Disturbances of the drainage mechanism that maintains a constant fluid pressure in the aqueous humor may cause an increase in the pressure, a condition called glaucoma.

Histamine Definition - What is Histamine?

Histamine is a chemical that is normally present in tissue mast cells and certain white blood cells circulating in the body.
Histamine is involved in the immune system, digestion system and central nervous system.
Histamine as a neurotransmitter communicates important messages from the body to the brain, and it is also a component of stomach acid, which is what helps us in breaking the food in our stomach.
Large amounts of histamine are released in response to an injury or in conjunction with an antigen-antibody reaction, such as an allergic reaction.
Histamine causes contraction of pulmonary smooth muscle (bronchocon-striction) that results in an asthma-like disorder.
Histamine also dilates small blood vessels and increases their permeability.
These actions are responsible for histamine headache and the typical wheal-and-flare allergic skin reaction.
Histamine is a potent stimulant of acid secretion in the stomach.
Epinephrine and H1-receptor blocking antihistamines reverse the actions of histamine on smooth muscles;
H2-receptor blocking antihistamines, such as cimetidine or ranitidine, reverse the gastric acid stimulant action of histamine.

Histamine Intolerance Symptoms

All people have an enzyme (diamine oxidase) which breaks down any histamine that we absorb from a histamine-containing food.
When normal person eats food which contains histamine, it does not affect him. However, some people have a low level of the diamine oxidase enzyme. When these people eat too many histamine-rich foods, they may suffer ‘allergy-like’ symptoms, called Histamine intolerance.

Some of the Histamine Intolerance Symptoms, include:
  • Abdominal pain,
  • Flatulence,
  • Diarrhoea,
  • Headache,
  • Pruritus (itching),
  • Blepharedemas (puffy eyes),
  • Urticaria (hives),
  • Runny nose when eating bananas, avocados, or eggplants
  • Itchy tongue
  • Menstrual cycle problems
  • Respiratory obstruction (difficult breathing),
  • Tachycardia (racing heart),
  • Extrasystoles (palpitations)
  • Low blood pressure

How can the adverse effects of histamine be treated or prevented?

The most rapidly effective treatment is epinephrine (adrenaline), which is usually given by injection. Antihistamines are better at preventing reactions than treating them and are useful if an allergic reaction, such as hay fever, is expected.

How Does the Human Eye Work?

Human Eyes are part of the organ of sight, with almost perfect sphere shape, about one inch in diameter.
Each eye is protected at its back and sides by the bones of the skull and at the front by two lashed eyelids.
The outer covering of the eye, the sclera or "white," is both protective and structural. 
Light penetrates the sclera only at the front of the eye, where the outer surface bulges into the transparent cornea, a delicate structure overlaid with a thin defensive membrane, the conjunctiva.
Under each upper eyelid is a tear-secreting lacrimal gland whose constant activity keeps the conjuctiva moist and free from germs.
Light entering the eye passes through the cornea and then through a watery fluid, the aqueous humor, in the front of the eye. 
Behind the fluid is the iris, a ring of muscle with a central hole, the pupil. 
The cornea focuses light rays so that they pass through the pupil. 
The iris determines how much light enters the eye. 
In dim light its muscles relax to let in more light; in bright light its muscles contract to reduce pupil size and restrict light entry.
How Does the Human Eye Work?

The fine focusing of light is achieved by the lens, a soft, transparent structure lying behind the iris. The lens is held in place by ligaments attached to internal eye muscles. 
The actions of these muscles bring about changes in the shape of the lens so that close and distant objects can be focused upon. 
For viewing near objects, the muscles make the lens shorter and fatter; for viewing distant objects, the lens becomes longer and thinner. This process is known as accommodation.
From the lens, light passes through the thick jelly (vitreous humor) that fills the center of the eye. The light is projected onto the retina, a light-sensitive layer inside the sclera from which it is separated by the choroid, a dark layer of tissue rich in blood vessels.
The retina contains two sorts of light-receptor cells: - rods, which detect shades of black and white; and - cones, which are sensitive to color.
In response to light, the rods and cones generate nerve impulses that pass along the optic nerve to the brain to be interpreted as vision. The concentration of cones is densest at a single spot called the fovea. 
The fovea is the region that gives the greatest visual sharpness.
Visual sharpness (acuity) depends on the number and density of the rods and cones, since each cell can record only the presence of light and, in cones, its color. 
There are about 10 million cones and 100 million rods in each eye.
Where the optic nerve leaves the back of the eye, there are no rods or cones; this is called the blind spot.

Human body types – Ectomorph, Mesomorph, Endomorph

Endomorph, ectomorph and mesomorph are three hypothetical body types first proposed around the turn of the century to explain certain aspects of personality.
This system of categorization was established during the 1940's, by William Herbert Sheldon, Jr. (November 19, 1898 - September 17, 1977).

Human body types – Ectomorph, Mesomorph, Endomorph


The endomorph's body is characterized by a round head, a round and large abdomen, large internal organs, rather short arms and legs with slender wrists and ankles, and a large proportion of body fat.
Endomorph is a person characterized by a predominance of structures developed from the endodermal layer of the embryo. Such a person is inclined to be soft-skinned and fat; some also ascribe to endomorphs the characteristics of being easy-going and good-natured.


The mesomorph has the body of a classical athlete: a square head, a large heart, broad and muscular chest and shoulders, arms and legs with powerful muscles, and little body fat.


The ectomorph's body is essentially linear in shape: a thin face with a high forehead, a narrow chest and abdomen, long and thin arms and legs, little muscle, and a minimal amount of body fat.

These three shapes rarely occur in their classical forms. Most people can be described as a combination of two of the three types.

Cell membrane function

Cell Membranes enclose the entire cell, the nucleus, and all the organelles. The membranes hold the cell and each of its parts together.
Most membranes consist of a double layer of a fatty substance called phospholipid. Proteins occur at various points and extend to different depths within the double layer of phospholipids.
Only needed materials can enter the cell and its parts because of the structure and chemical composition of the membranes. 

Cytoplasm definition and function

The Cytoplasm is the entire cell except the nucleus. Proteins are made in the cytoplasm, and many of the cell's life activities take place there.
Many tiny structures called organelles are located in the cytoplasm.
Each has a particular job to do. These organelles are called mitochondria, lysosomes, the endoplasmic reticulum, centrioles, and Golgi bodies.

Mitochondria - What is mitochondria?

Mitochondria are the power producers of the cell. A cell may contain hundreds of mitochondria. These sausage-shaped structures produce almost all the energy the cell needs to live and to do its work.

Lysosome function and definition

Lysosomes are small, round bodies containing many different enzymes, which can break down many substances. For example, lysosomes help white blood cells break down harmful bacteria.

Endoplasmic Reticulum

Endoplasmic Reticulum is a complex network of membrane-enclosed spaces in the cytoplasm. The surfaces of some of the membranes are smooth. Others are bordered by ribosomes—tiny, round bodies that contain large amounts of RNA. Ribosomes are the cell's manufacturing units. The proteins the cell needs in order to grow, repair itself, and perform hundreds of chemical operations, are made on the ribosomes.


Centrioles look like two bundles of rods. They lie near the nucleus and are important in cell reproduction.

Golgi Bodies

Golgi Bodies, also called Golgi complex or Golgi apparatus, consist of a stack of flat, bag-like structures that store and eventually release various products from the cell.

Bell's palsy - What is Bell's Palsy?

Bell's palsy is paralysis of the muscles of the face, caused by acute malfunction of, or damage to, the nerve that supplies them.
An attack frequently occurs without apparent cause.

Symptoms of Bell's palsy

Facial features lose their symmetrical arrangement, and the mouth droops at one corner. Paralysis of
the muscles results in loss of control over saliva or tears, so that the patient may dribble or appear to  cry.

Bell's palsy treatment

It is important that a physician is consulted immediately because swift treatment with corticosteroid drugs may help. Many patients recover spontaneously; about 70 percent recover completely within 4 to 6 weeks, and about 20 percent make a partial recovery.
Surgery to the affected nerve may restore partial nerve function.

Behavior therapy Definition - What is Behavior therapy?

Behavior therapy, often used interchangeably with behavior modification, is a form of psychological treatment based on learning theory.
Behavioral therapists believe that maladaptive behavior and thinking is learned or conditioned and, therefore, can be unlearned.
New, more constructive behavior can then be taught or shaped.
Little attention is paid to intrapsychic or unconscious forces. Instead, behavior therapy focuses directly on overt behavior.
Behavior therapy has been found to be particularly effective with anxiety and fear, using techniques such as relaxation training, desensitization, and assertiveness training. To increase the probability of success, behavioral therapists also attempt to remove the reinforcing consequences of maladaptive behavior as well as to reward appropriate behavior.

Decubitus ulcer - Pressure sore, Bedsore

Decubitus ulcer or also known as Bedsore or pressure sore, is a skin and tissue injury caused by impaired blood supply and tissue nutrition.
It is caused by prolonged pressure over bony prominences due to lying too long in the same position.
The parts of the body most likely to be affected are the pressure areas: the bone at the lower end of the spine (the sacrum), the buttocks, and the heels.
The shoulder blades and elbows may also develop these sores.
The area first becomes slightly red with cracked skin, which turns dark blue before ulcerating as dead tissues disintegrate.

Pressure ulcer prevention

Patients who cannot move themselves must be moved every few hours. Patients must not sit in bed or in a chair for long periods.
The patient should be lifted, not slid, when moved.
The skin is to be kept clean and dry.
Bedclothes must be kept clean, dry, and free from creases.
Additional protection can be given to the pressure areas by using foam pads and real or artificial sheepskin.
A variety of air mattresses and other types of beds are available to help prevent decubitus ulcers.
A well-balanced diet helps to prevent bedsores.

Pressure ulcer can be prevented by using variable pressure bed

Decubitus ulcer treatment

The patient should not lie on the ulcer, although this may be awkward.
The ulcer should be cleansed according to a physician's advice.
Specific ointments or dressings may be prescribed.
Care must be taken to turn the patient frequently to treat the bedsore and prevent new ones.
The sores generally heal over a period of time if they are carefully tended.
The best treatment, however, is prevention.

Bedbug and Bed bug bites

Bedbug (Cimex lectularius or cimex hemipterus) is a small blood-sucking insect that can infest bedding and bite humans or other animals.
The insect is red-brown, oval, flat, and wingless.

Bed bug bites symptoms

Bedbug bite is painful and causes swelling, itching, and sometimes infection.
It may transmit relapsing fever.

Bed bugs treatment

The bite can be treated with a corticosteroid cream or other anti-inflammatory preparation.
The infested bedroom furniture should be disinfected.

Addisons Disease - What is Addisons Disease?

Addison's disease is a rare medical condition that results from insufficient production by the adrenal gland of several vital hormones.
It is caused by a disorder of the adrenal glands themselves or by the failure of the part of the pituitary gland that produces ACTH, the hormone that stimulates the adrenal glands.
Addison's disease is most common during middle age. Stopping steroid medications suddenly and without medical supervision can produce a life-threatening Addisonian crisis.

Addison disease symptoms:

Common symptoms of Addisons disease may include weakness and dizziness caused by low blood pressure, vomiting, diarrhea, anemia, loss of weight, and a brownish color of the skin and the membranes lining the mouth.
It is difficult to diagnose the condition because it is slow to develop and because there may be occasional, temporary improvements in the patient.
Tests can reveal the low amount of adrenal hormones in the blood and a disturbance in the balance of salts in the body fluids.

Addison disease treatment:

Treatment of Addisons disease following a correct, early diagnosis can be highly effective. The missing hormones are replaced and recovery is generally speedy.