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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. Explore more: Arts and crafts for kids Volcano School Project - Arts and crafts for kids... My Star File - Arts and crafts for kids... Treasure map for kids - Arts and crafts for kids... Wacky animal whizzer - Art projects for kids... How to Make a Paper Banger - Arts and crafts for kids... How To Make An Ant Farm for kids? - Arts and crafts for kids...

The paper ball is very interesting project consisting of three circles of paper A, B and C. The three parts should be inserted appropriately one into another in order to make the ball.

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. 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). Explore more: Arts and crafts for kids Volcano School Project - Arts and crafts for kids... My Star File - Arts and crafts for kids... Treasure map for kids - Arts and crafts for kids...

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.

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 bui...

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 gu...

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 servic...

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 firs...

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 sig...

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. 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. - - - - - - - - - Read more about:  Why do wisdom teeth cause so many problems? - - - - - - - - - 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 invente...

Throughout 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...

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.

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. 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.

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. Th...

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.

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 t...

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 pituitar...

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 ...