How to Make a Pinwheel – Art Projects For Kids

On a square sheet of paper cut from the corners four straight-line incisions. Fold toward the middle every second end, and pierce all four tops with needle trough the center of the sheet.

How to Make a Pinwheel:

Attach the end of the needle to a wooden stick and the pinwheel is finished.
Before you make the pinwheel, it can be colored in different colors and also you can experiment with different kinds of materials as replacement for the paper.
You can place more than one pinwheels on one stick and use it as a scarecrow.

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How to Make a Paper Banger - Art projects for kids

To make this harmless and loud toy – the Paper Banger, we need strong sheet of paper size 6,3 x 9,5 inches (16 x 24 cm)  (or other sheet of paper with edge ratio 2:3).

How to make paper bangers?

First fold the sheet in half along the long side to mark the middle of the sheet.
Then fold the edges as shown on image A.
Again fold the paper in half, to mark the middle, and fold the edges as shown on image B and C.
Make one more fold in half (image D) and the paper banger is finished.
How to Make a Paper Banger

Grab the edge and swing as hard as you can but have in mind that there should be a slight opening between the two sides in order for air to enter and make the bang during the swing (image E).

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Where is the Panama Canal?

One of the most important construction projects in the history of mankind was the building of the Panama Canal.
The Panama Canal has influenced the development of trade across the globe.

The construction of the canal, shortened the distance between many ports on the Atlantic and Pacific oceans for about 8,000 miles (13,000 kilometers).
The Panama Canal is located in the country Panama in Central America.

Panama Canal - What is the Panama Canal?

One of the most important construction  projects in the history of mankind was the building of the Panama Canal.
The Panama Canal has influenced the development of trade across the globe.
The construction of the canal, shortened the distance between many ports on the Atlantic and Pacific oceans for about 8,000 miles (13,000 kilometers).
According to the first idea, the Panama Canal was supposed to be built by the French at the level of the sea, with depth of 30 feet (9 meters), and width at the bottom of 72 feet (22 meters).
However, the French plan was not realized and in 1904 The United States accepted the construction of the canal.
The French plan to dig a canal below the water level, from one ocean to the other, was dangerous.
In fact, if the differences between high and low tide on one side of the ocean were larger than the other, there would be major currents trough the channel.
This plan also required a lot more digging.
Given these problems, it was decided to build a canal with locks, which meant that it must provide water at a higher altitude, in order to meet more parts of the channel.
This has been achieved with the erection of dams on the Chagres River.
Panama Canal
Dams form one kind of staircase, through which the ships come into the channel.
Ships are raised in some places where the water level is higher, and then descend to the other places.
Almost half of the canal passes through Lake Gatun.
Ships coming from the Atlantic are raised to the level of the lake by 92 feet (28 meters) through a series of three dams.
On the other side - Pacific Ocean there is one notch 8 miles (13 kilometers) long.
The ships then are being suspended 33 feet (10 meters) in the first dam and 60 feet (18 meters) through two other dams, so go down to sea level.
Through the dams the ships are pulled with electric locomotives moving along the coast. Today, trough the dams even the largest ships can move.
Panama Canal - Where is the Panama Canal

History of Hospitals - First Hospital In The World?

The need for care of the weak and sick exists ever since the earliest days of human society. However, people much later came to the idea to set up a hospital.
Old Greeks for example, didn't had any public institution for the care of the sick. Some doctors had their rooms for operation, in which they could do their job, but they were so small that they could accommodate only one patient.
Romans at the time of the wars founded hospitals in which they treated the wounded and sick soldiers. Later, also the larger cities of the Roman Empire got hospitals that were maintained with resources from public funds.
With the rise of Christianity, the church took care of patients, and the largest number of hospitals in the Middle Ages was under the auspices of the monasteries, so that the priests and nuns cared for the patients.
Custom traveling to pilgrimage also helped the establishment of hospitals.
Traveling to places of pilgrimage took long time, and the pilgrims had rest in small guestrooms (inns) on the roads. These inns were associated with monasteries and took over the care of the sick and weary travelers.
Since the conditions of life in the Middle Ages were not especial, and the hygiene was poor, the hospitals of that era were dirty and disorganized. Many hospitals were overcrowded, so it happened that more than one patient lied in one bed.
In the 17th century general living conditions improved and the people felt that the state is obligated to take care of its ill residents.
But only in the 18th Century, general public hospitals begin to open in the larger European cities.
In North America, the first hospital was erected by Cortes in Mexico in 1524.

History of the Post Office

Today, it is quite normal that we send and receive by mail letters and packages. However, although the idea of the postal service existed long time ago, it was implemented very slow.
In the old days, in ancient Rome, the government managed the delivery of messages, but those messages were related exclusively to government issues.
During the Middle Ages, an association of traders and some larger universities held a special and limited postal services, which were used exclusively by its members.
It was only in the 16th century, when governments begun to introduce regular postal service, firstly because they thus were able to monitor suspicious correspondence, and also because the postal service constituted a source of income, and finally, because it provided the necessary services to the public. Today as the basis for the provision of postal services remained practically only this third reason.
King Henry VIII had a postal service in England, and his successors expanded this service. In 1609 only official postmen could transfer the messages in the form of letters. However, London traders in 1680 founded their own service for delivery of letters in the city and its surroundings. It was called "Penny - mail" – one letter cost one penny. This Post office operated very successfully, so the English government took it over and continued its work until 1801.
The entire postal system was finally transformed in 1840. Postage stamps were implemented and single tariff for all the places in the country, and difference existed only in relation to the weight of the mail.
All other countries have organized their postal system modeled on the one in the UK.

First Bank In The World - When was the first bank established in the world?

History of Banking

Today banks provide a variety of services, but they actually have two main tasks.
The first task is to accept deposits from people and keep their money until they need them again.
The second task is to give money loans to people that they are willing to pay back with interest.
Having this definition in mind, we can say that the banking is old as mankind.
In ancient Babylon, Egypt and Greece people were engaged in banking.
The temples were usually the place where the money were deposited.
In Rome, in 210 BC with decree published by the Forum, the location of the money changers was determined.
However, in the Middle Ages, taking interest was considered a sin, and some countries have banned their citizens to establish a bank.
Of course, some people were still doing it.
Thus, in the Middle Ages money changers in Italy did their business on the street, on the bench, which on Italian is called “banco”, and hence came the name "bank".

When was the first bank established in the world?

Modern banking first emerged in Venice in 1587, when the “Banco di Rialto” was founded. 

The bank received deposits and allowed the investors to write checks based on money they had in the bank.
In 1619 “Banco del Giro” took over “Banco di Rialto” and started to give receipts on the invested silver and gold, which were used as a cash receipts.
Bank of Amsterdam, founded in 1609, also issued certificates which were used as a "bank's money."
In England the jewelers were also bankers until 1694, when the Bank of England was founded, which held a monopoly on public banking in England until 1825.

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Heliograph - Communicating by light

What is Heliograph?
Sometimes when you are in open country, you may catch a flash of sunlight on the windshield of a car many miles away.
The windshield acts like a mirror and reflects the light.
You have probably shone a flashlight beam against a wall or ceiling and watched the spot of light.
Cover the mirror or flashlight with your hand, and the light disappears.

Put these two ideas together, and you have one of the oldest ways of communicating in the world—signalling by the light of the sun.
The ancient Greeks signaled to each other in this way.
They used an instrument called a heliograph. 
The name comes from the ancient Greek words for “sun” and “writing.”
A heliograph can be seen up to 30 miles (48 kilometers) away on a clear day without a telescope.
The modern heliograph is mounted on a tripod, like a camera.
It can turn in any direction.
The mirror flashes when it is directed at the sun and can then be dipped away or covered with a shutter.
If the signaler wants to send a message in a direction away from the sun, a second mirror is used to reflect light on to the first.

Heliograph messages are sent in Morse Code - Learn more...
You can send heliograph messages using a simple mirror. Tilt the mirror so that it catches the sun's rays. Then reflect the rays towards your friend.
SIgnaling by Heliograph, Signal Corps, Fort Omaha, Neb. 1908
SIgnaling by Heliograph, Signal Corps, Fort Omaha, Neb. 1908

Messages in the dark

A heliograph can be used only in the daytime when the sun is shining.
But at night, light messages can be sent using an Aldis lamp.
This is a powerful searchlight. It has a shutter that can be moved to block out the light and also make the dots and dashes of Morse code.

How to Make a Heliograph - By R. B. Huey

Excerpt from the book:
THE BOY MECHANIC - BOOK 2 - 1000 THINGS FOR BOYS TO DO
PUBLISHED 1915, BY H. H. WINDSOR CHICAGO - POPULAR MECHANICS CO. PUBLISHERS
The heliograph which is used in the army provides a good method of sending messages by the reflection of the sun's rays. In the mountains there are stations from which messages are sent by the heliograph for great distances, and guides carry them for use in case of trouble or accident. The wireless telegraph delivers messages by electricity through the air, but the heliograph sends them by flashes of light.

The main part of the instrument is the mirror, which should be about 4 in. square, set in a wood frame and swung on trunnions made of two square-head bolts, each 1/4 in. in diameter, and 1 in. long, which are firmly held to the frame with brass strips, 1/2 in. wide, and 3 in. long. The strips are drilled centrally to admit the bolts, and then drilled at each end for a screw to fasten them to the frame. This construction is clearly shown in Fig. 1.
How to Make a Heliograph  Fig 1
Detail of the Parts for Making the Mirror and Sight Rod Which are Placed on a Base Set on a Tripod Top, the Whole being Adjusted to Reflect the Sun's Rays in Any Direction Desired (Fig. 1)

A hole is cut centrally through the backing of the frame and a small hole, not over 1/8 in. in diameter, is scratched through the silvering on the glass. If the trunnions are centered properly, the small hole should be exactly in line with them and in the center.

How to Make a Heliograph  Fig 2

A U-shaped support is made of wood strips, 3/8 in. thick and 1 in. wide, the length of the uprights being 3-1/2 in. and the crosspiece connecting their [184] lower ends a trifle longer than the width of the frame. These are put together, as shown in Fig. 2, with small brackets at the corners. A slot, 1/2 in. deep and 1/4 in. wide, is cut into the upper end of each upright to receive the trunnions on the mirror frame. Nuts are turned on the bolt ends tightly, to clamp the standard tops against the brass strips on the mirror frame. The cross strip at the bottom is clamped to the base by means of a bolt, 1-1/2 in. long. The hole for this bolt should be exactly below the peephole in the mirror and run through one end of the baseboard, which is 3/4 in. thick, 2 in. wide and 10 in. long.

How to Make a Heliograph  Fig 3

At the opposite end of the base, place a sighting rod, which is made as follows: The rod is 1/2 in. in diameter and 8 in. long. The upper end is fitted with a piece of thick, white cardboard, cut 1/4 in. in diameter and having a projecting shank 1 in. long, as shown in Fig. 3. The rod is placed in a 1/2-in. hole bored in the end of the baseboard, as shown in Fig. 2. To keep the rod from slipping through the hole a setscrew is made of a small bolt with the nut set in the edge of the baseboard, as shown in Fig. 4.

How to Make a Heliograph  Fig 4

The Parts in Detail for Making the Tripods... (Fig. 5, Fig. 6)
How to Make a Heliograph  Fig 5, 6
The tripod head is formed of a wood disk, 5 in. in diameter, with a hole in the center, and three small blocks of wood, 1 in. square and 2 in. long, nailed to the under side, as shown in Fig. 5. The tripod legs are made of light strips of wood, 3/8 in. thick, 1 in. wide and 5 ft. long. Two of these strips, nailed securely together to within 20 in. of the top, constitute one leg. The upper unnailed ends are spread to slip over the blocks on the tripod top. These ends are bored to loosely fit over the headless nails driven part way into the block ends. One tripod leg is shown in Fig. 6.
How to Make a Heliograph  Fig 7,8
...and the Shutter for Flashing the Light,... (Fig. 7, Fig. 8)

The screen, or shutter, is mounted on a separate tripod and is shown in Fig. 7. Cut out two slats, 3/8 in. thick, 2-1/2 in. wide and 6 in. long, from hard wood, and taper both edges of these slats down to 3/16 in. Small nails are driven into the ends of the slats and the heads are filed off so that the projecting ends will form trunnions for the slats to turn on. Make a frame of wood pieces, 3/4 in. thick and 2-1/2 in. wide, the opening in the frame being 6 in. square. Before nailing the frame together bore holes in the side uprights for the trunnions of the slats to turn in. These holes are 1-3/4 in. apart. The frame is then nailed together and also nailed to the tripod top. The shutter is operated with a key very similar to a telegraph key. The construction of this key is shown in Fig. 7. A part of a spool is fastened to a stick that is pivoted on the opposite side of the frame. The key is connected to the slats in the frame with a bar and rod, to which a coil spring is attached, as shown in Fig. 8. Figure 9 shows the positions of the tripods when the instrument is set to flash the sunlight through the shutter. The regular telegraph code is used in flashing the light.
How to Make a Heliograph  Fig 9
...and Diagram Showing the Location of the Tripods to Direct the Light through the Shutter (Fig. 9)

To set the instrument, first turn the cardboard disk down to uncover the point of the sight rod, then sight through the hole in the mirror and adjust the sight rod so that the tip end comes squarely in line with the receiving station.
When the instrument is properly sighted, the shutter is set up directly in front of it and the cardboard disk is turned up to cover the end of the sight rod.
The mirror is then turned so that it reflects a beam of light with a small shadow spot showing in the center made by the peephole in the mirror, which is directed to fall on the center of the cardboard sighting disk. It will be quite easy to direct this shadow spot to the disk by holding a sheet of paper 6 or 8 in. in front of the mirror and following the spot on the paper until it reaches the disk.
The flashes are made by manipulating the key operating the shutter in the same manner as a telegraph key.

Morse Code for Kids and Morse Code Alphabet

In 1832, an American artist sailed home from Europe. He had spent some time painting in Europe and hoped to sell his pictures when he arrived home. His name was Samuel Morse.
The journey on the ship was to change Samuel Morse’s life.
Samuel Finley Breese Morse

Read more: How to make a morse code machine...

He met a young chemist from Boston, named Charles Jackson, who showed him how an electromagnet works. Morse became interested in electricity and in the idea of sending messages along electric wires.
Samuel Morse was one of the first people to make an electric telegraph. 
An electric telegraph uses an electric current to send messages along a wire.
morse code key - electric telegraph uses an electric current to send messages along a wire.

Operators of this electric telegraph machine sent messages down the line in Morse Code.

Morse Code Alphabet

This telegraph was not what made Morse famous. He gave his name to the code of dots and dashes which he invented.
Until this time, most long distance messages were sent by semaphore.
The problem with the electric telegraph was that an electric current can be arranged in only two ways.
Either the current is flowing and it is “On,” or it is “Off.”
Somehow a way had to be found of using the flow of current to make a code that could be sent along the wires.
Morse’s answer was to make codes for different letters and numbers out of short and long bursts, or pulses, of electric current.
He called these dots and dashes.
Using dots and dashes in different orders made the different codes.
The Morse “key ” (Morse Code Key) which makes the pulses is a kind of switch that turns the current on and off.
Messages sent by electric telegraph would be marked by the receiving machine on a moving strip of paper.
Then the telegraph operator would decode the dots and dashes into ordinary letters and numbers.
But operators who used Morse Code soon became skilled at “reading” the messages directly from the clicks made by the machine.

The international, or continental, Morse Code:
morse code chart for kids printable
Morse code chart for kids printable
Morse invented a different dot and dash pattern for each letter and number.The emergency signal in Morse Code, SOS, is known to sailors all over the world. They use it to call for urgent help if a ship is in danger.
Morse Code, SOS code ...---...
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Semaphore Alphabet

Semaphore AlphabetThroughout history, armies and navies have sent messages across battlefields.
Simple orders like “Advance” or “Retreat” could be given by bugle calls or cannon-fire.
But sending reports of the battle back to headquarters needed a different system.
During the 1790’s, a Frenchman called Claude Chappe invented a signaling system called semaphore.
This was a system of sending signals by means of two jointed arms at the tops of tall posts. These arms could be moved to different positions to show different letters of the alphabet.
Each semaphore station was built on a hill so that it could be seen, using a telescope, from the next station in any direction. In this way, messages could be relayed over long distances from one station to the next.
Semaphore stations on the coast would send messages to ships at sea.
On the battlefield, there might not be a semaphore station, but messages could be sent by stationing signalers with large flags on nearby hills.
They used the same code as the semaphore arms.
An expert signaler could send or receive up to 25 letters a minute and messages could be relayed nearly 155 miles (250 kilometers) in 15 minutes.





Games for youth groups – The relay game

The relay game - Games for youth groups 

Playing the relay game shows how easy it is for relayed messages to be changed or misunderstood.
Make up a group of eight or more people in a circle.
One person whispers a 10-word message to the next, who whispers it on, and so on around the circle.
No one may whisper the message more than once.
When the message has gone around the circle, the last person calls it out.
The person who started calls out their message.
You can make the game more difficult by starting two messages going in opposite directions at the same time.

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Periwinkle Flowers - Rosy Periwinkle - Cure From The Rain Forests

The tropical rain forests provide scientists with an enormous variety of plants. Some of these plants contain special chemicals that can be used as medicines.
Scientists in the United States have found some tropical rain forest plants that might be used to fight against cancer.
About 30 years ago, scientists who were trying to find a cure for cancer investigated a plant called the Rosy Periwinkle.
This grows in the tropical forests of Madagascar, an island off the coast of Africa.
For many years, local healers had used this plant as a medicine. The scientists found that chemicals in the rosy periwinkle helped to treat cancer. It was especially useful for treating children with cancer of the blood, known as leukemia.
Treatment using the rosy periwinkle has meant that more people can now be cured of cancer.

Chemicals in the rosy periwinkle can help to treat leukemia.


What Protist Causes Malaria?

Some diseases are caused by larger creatures called protists and also by worms.
These larger invaders are sometimes more difficult to kill than the smaller ones.
Malaria and sleeping sickness are two diseases caused by protists. 
Protists are soft, jellylike creatures that usually need to be surrounded by plenty of water in order to survive.
As our bodies contain lots of water, they can live inside us.
Not all protists live inside people or other animals.
Some live harmlessly in soil and water.
Protists are not as easily spread from one person to another as some microbes, such as bacteria and viruses. But they have special ways of infecting people. Some harmful protists are spread by biting insects.
These flies spread sleeping sickness, and mosquitoes spread malaria and yellow fever.
mosquito
When a mosquito bites a person, it sucks up blood.
At the same time, it may infect the person's blood with the protist that causes yellow fever.

What is a Vaccination and Why is it Important?

Some diseases which are caused by viruses, such as cholera, will make you ill only once.
How does your body stop you from having some diseases more than once?
The first time you have the virus, your body will take some time to make antibodies against it.
That is why you are ill for a while.
As soon as the antibodies start working, you begin to feel better.
Once you are better, your body is repeatedly able to make the antibodies for that particular virus.
If the virus enters your body again, your body can make antibodies much more quickly than the first time.
The antibodies defeat the virus without your knowing about it.
You are now immune to that virus, which means that your body can protect itself against this disease in the future.

Changing viruses

Some viruses can’t be kept out so easily. They keep changing their form. The antibody produced against the original form won’t recognize the new form. Thus your body needs extra time to develop a new antibody for each form.
The viruses that cause the common cold and influenza keep changing like this, so we have these illnesses again and again.
The virus that causes AIDS can also change its form.

Special protection from disease

Doctors have a way of helping our bodies to fight against some diseases.
This is done by giving people vaccinations.
When you have a vaccination against cholera, a tiny amount of the cholera virus, which has been specially treated, is injected into your body through a needle.
Your body then makes antibodies to fight the virus.
So when the cholera virus tries to attack your body, you are immune to the disease that it causes.
What is a Vaccination and Why is it Important
Vaccinations are a major part of the worldwide fight against diseases, such as cholera, tuberculosis, and polio.
Smallpox, the first disease for which a vaccine was used, has almost completely disappeared.
But for some diseases, such as AIDS and the common cold, doctors still haven’t found a vaccine.

Hypothalamus For Kids - What does the Hypothalamus do?

What does the Pituitary Gland do?

The balance of hormones in your blood is controlled by the pituitary gland, which lies just below the brain.
The pituitary gland produces hormones which control many of the body’s activities.
Large numbers of nerve cells and blood vessels link the pituitary gland to a part of the brain called the hypothalamus.

What does the Hypothalamus do?

The hypothalamus controls the pituitary gland by sending “on” and “off ” messages through the nerve cells and the bloodstream. These messages affect the pituitary gland with regard to the releasing of its hormones.

Where is the Pituitary Gland Located and What does the Pituitary Gland Do?

Where is the Pituitary Gland Located
Hormones control the different parts of your body, so that everything is regulated. Hormones are regulators of chemical and growth activity in the body.
A special kind of hormone, called growth hormone, helps the long bones to grow. Children who do not produce enough of this hormone may not grow as tall as they would be able to grow with the hormone.
The balance of hormones in your blood is controlled by the pituitary gland, which lies just below the brain.
The pituitary gland is the main hormone-producing gland.
It lies just underneath your brain. 
The pituitary gland produces many different hormones, like the ones that control your growth and others that control your kidneys.
The pituitary gland produces hormones which control many of the body’s activities.
Large numbers of nerve cells and blood vessels link the pituitary gland to a part of the brain called the hypothalamus. 
The hypothalamus controls the pituitary gland by sending “on” and “off ” messages through the nerve cells and the bloodstream.
 These messages affect the pituitary gland with regard to the releasing of its hormones.

Hormone definition for kids - What are Hormones?

Are you tall for your age, or short?
How tall you grow depends mostly on chemical substances called hormones, which move around your body in your blood.
Some hormones cause the cells in your body to make more protein. They then make the cells grow and divide, so that all of your body gets bigger.
Because hormones are going around in your blood, they reach every cell in your body. So all your cells grow and divide at your normal rate.
Can you imagine how it would be if some-parts of your body grew faster than others? 
This is why hormones are so important.
Hormones control the different parts of your body, so that everything is regulated.
Hormones are regulators of chemical and growth activity in the body.
A special kind of hormone, called growth hormone, helps the long bones to grow. Children who do not produce enough of this hormone may not grow as tall as they would be able to grow with the hormone.
The balance of hormones in your blood is controlled by the pituitary gland, which lies just below the brain.
The pituitary gland produces hormones which control many of the body’s activities.
Large numbers of nerve cells and blood vessels link the pituitary gland to a part of the brain called the hypothalamus. 
The hypothalamus controls the pituitary gland by sending “on” and “off ” messages through the nerve cells and the bloodstream.
These messages affect the pituitary gland with regard to the releasing of its hormones.
hypothalamus

Human Spinal Cord - What is the function of the spinal cord and What is Reflex?

Human brain receives messages from all over the body and sends messages in return.
This is how coordination of all the different parts of body takes place.
But how do the messages travel to and from the brain?
The messages are carried along by nerve cells.
Throughout the body, there is a network of these cells. Nerve cells use impulses of electricity to carry messages.
Nerve cells are ball-shaped with thin branches extending from them. The shorter branches, called dendrites, take in messages from other nerve cells.
The longer branches carry messages out of the nerve cell. These branches are called axons.
The axons connect with other nerve cells and may pass their messages on to different parts of the body, such as muscle cells, glands, or organs.
The brain is made of billions of nerve cells, each one making a network of connections with other nerve cells. When you think, millions of tiny electric currents are running through these networks.
Even when you are asleep, millions of electric currents pulse through your brain, because the brain is busy keeping you alive.

What is the function of the spinal cord?

The base of the brain, the brain stem, extends into the spinal cord. 
This is a thick bundle of nerve cells. It runs down the back inside the backbone. 
Along the way, nerves branch off from the spinal cord. 
Some go to the arms, others to the lungs, heart, liver, stomach, and other internal organs. 
Lower down, nerves branch off to the legs and feet.

What Is Reflex?

Human leg muscles flex and move to allow them to stand up because their brain has sent them messages on what to do.
But there are some movements, such as drawing our hand away from something hot, which do not involve the brain.
These are called reflexes. Reflexes help to protect us from danger. 
Blinking our eyes as something comes very near to our face is another reflex.
Doctors can test whether our reflexes are working properly by using the knee-jerk test.
What Is Reflex

The person sits on a chair with one leg crossed over the other.
The doctor taps a spot just below the knee of the top leg, and the persons leg jerks into the air.
We can’t control it.
When our knee is tapped, a message travels up a nerve in our thigh to our spinal cord.
It does not go to the brain.
The spinal cord sends a message straight back to a nerve connected to the thigh muscle.
This muscle contracts suddenly and our leg jerks upwards.