Hovercraft

Hovercraft

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A hovercraft is a vehicle supported on a cushion of air supplied by a powered fan mounted on the craft.

The hovercraft was invented by Christopher Cockerell in 1956. The theory behind one of the most successful inventions of the 20th century, the Hovercraft, was originally tested in 1955 using an empty KiteKat cat food tin inside a coffee tin, an industrial air blower and a pair of kitchen scales. Sir Christopher Cockerell developed the first practical hovercraft designs, these led to the first hovercraft to be produced commercially, the SRN1.

Christopher Cockerell's idea was to build a vehicle that would move over the water's surface, floating on a layer of air. This would reduce friction between the water and vehicle. To test his hypothesis, he put one a smaller can inside a larger can and used a hairdryer to blow air into them. The downward thrust produced was greater when one can was inside the other rather than air just being blown into one can.

Radio and its Invention

Radio owes its development to two other inventions, the telegraph and the telephone, all three technologies are closely related. Radio technology began as "wireless telegraphy". Radio can refer to either the electronic appliance that we listen with or the content listened to. However, it all started with the discovery of "radio waves" - electromagnetic waves that have the capacity to transmit music, speech, pictures and other data invisibly through the air. Many devices work by using electromagnetic waves including: radio, microwaves, cordless phones, remote controlled toys, television broadcasts, and more.

The Roots of Radio

During the 1860s, Scottish physicist, James Clerk Maxwell predicted the existence of radio waves; and in 1886, German physicist, Heinrich Rudolph Hertz demonstrated that rapid variations of electric current could be projected into space in the form of radio waves similar to those of light and heat. In 1866, Mahlon Loomis, an American dentist, successfully demonstrated "wireless telegraphy." Loomis was able to make a meter connected to one kite cause another one to move, marking the first known instance of wireless aerial communication.

Guglielmo Marconi

Guglielmo Marconi, an Italian inventor, proved the feasibility of radio communication. He sent and received his first radio signal in Italy in 1895. By 1899 he flashed the first wireless signal across the English Channel and two years later received the letter "S", telegraphed from England to Newfoundland. This was the first successful transatlantic radiotelegraph message in 1902.

Nikola Tesla

In addition to Marconi, two of his contemporaries Nikola Tesla and Nathan Stufflefield took out patents for wireless radio transmitters. Nikola Tesla is now credited with being the first person to patent radio technology; the Supreme Court overturned Marconi's patent in 1943 in favor of Tesla.

Growth of Radio - Radiotelegraph and Spark-Gap Transmitters

Radio-telegraphy is the sending by radio waves the same dot-dash message (morse code) used in a telegraph. Transmitters at that time were called spark-gap machines. It was developed mainly for ship-to-shore and ship-to-ship communication. This was a way of communicating between two points, however, it was not public radio broadcasting as we know it today. Wireless signals proved effective in communication for rescue work when a sea disaster occurred. A number of ocean liners installed wireless equipment. In 1899 the United States Army established wireless communications with a lightship off Fire Island, New York. Two years later the Navy adopted a wireless system. Up to then, the Navy had been using visual signaling and homing pigeons for communication.
In 1901, radiotelegraph service was instituted between five Hawaiian Islands. By 1903, a Marconi station located in Wellfleet, Massachusetts, carried an exchange or greetings between President Theodore Roosevelt and King Edward VII. In 1905 the naval battle of Port Arthur in the Russo-Japanese war was reported by wireless, and in 1906 the U.S. Weather Bureau experimented with radiotelegraphy to speed notice of weather conditions.
In 1909, Robert E. Peary, arctic explorer, radiotelegraphed: "I found the Pole". In 1910 Marconi opened regular American-European radiotelegraph service, which several months later, enabled an escaped British murderer to be apprehended on the high seas. In 1912, the first transpacific radiotelegraph service linked San Francisco with Hawaii.

Improvements to Radio Transmitters

Overseas radiotelegraph service developed slowly, primarily because the initial radiotelegraph transmitter discharged electricity within the circuit and between the electrodes was unstable causing a high amount of interference. The Alexanderson high-frequency alternator and the De Forest tube resolved many of these early technical problems.

Lee DeForest - AM Radio

Lee Deforest invented space telegraphy, the triode amplifier and the Audion. In the early 1900s, the great requirement for further development of radio was an efficient and delicate detector of electromagnetic radiation. Lee De Forest provided that detector. It made it possible to amplify the radio frequency signal picked up by the antenna before application to the receiver detector; thus, much weaker signals could be utilized than had previously been possible. De Forest was also the person who first used the word "radio". The result of Lee DeForest's work was the invention of amplitude-modulated or AM radio that allowed for a multitude of radio stations. The earlier spark-gap transmitters did not allow for this.

COFFEE..all the facts

Legend of coffee 

Some archaeological evidence shows that humans were eating the coffee berries as long ago as a hundred thousand years.

One legend says that a goat herder in Ethiopia observed his charges eating the red berries from a nearby tree and became excited. Trying them himself, he too felt a great lift. By 600 AD that magical berry, and the brew made from drying and grinding its seeds, had found its way to what is now Yemen, on the southern tip of the Arabian peninsula.

Stories tell of a native of India smuggling the precious seeds of the tree out of Arabia around 1650 AD, then planting them in the hills of Chikmagalur. Arabian law forbad the exporting of beans that could germinate, effectively controlling coffee trade for centuries. Whether myth or history, the fruit of those seeds now forms a third of India's large coffee output.

Coffee facts 

- The first Espresso machine was introduced in 1822 by the French, but it was the Italians who perfected and distributed it.
-There is less caffeine in dark roast than in medium roast. It is because, the longer the beans are roasted, the more caffeine burns off.

- During the American Civil War, soldiers, having used up all their coffee supplies, used roasted sweet potato and Indian corn as a substitute.

-On the contrary to popular belief, coffee does not grow in plain brown beans. It actually grows in red berries, which normally carry two green beans each. Sometimes there's only one bean in the berry - this single bean is called a peaberry.The coffee berries are often called cherries.

-Cowboy coffee? well, yes, cowboys are said to have had one of the most peculiar ways of making coffee - they put ground coffee in a clean sock and put in a pot of cold water over a campfire.

- Ants don't like coffee, so you can use coffee to keep them away from you plants or out of your rooms. Just put the used coffee grounds around the plants or on the ant tracks in your house.

-When Admiral Josephus "Joe" Daniels became Chief of Naval Operations he forbid to serve alcohol on board ships. As a result, coffee became the drink of choice, thus the term "Cup of Joe".

-At first in Europe the coffee was known as Arabian Wine.
-When beans begin to cool after roasting, they release approximately 700 chemical substances which make up the vaporizing aromas.

-The most expensive coffee in the world is called Kopi Luwak. Kopi is the Indonesian word for the coffee and luwak is a local name of the Asian Palm Civet. Also known as Civet coffee it is made from coffee berries that have been eaten and passed through the digestive tract of the Asian Palm Civet (Paradoxurus hermaphroditus). The beans inside the berries pass through the system undigested and are then defecated. The beans are then washed and given only a light roast to avoid destroying the complex flavors that are developed through the process.

-The word "coffee" entered the English language in 1598 via Italian word caffé, which in return is derived from Turkish kahve that came into being via Arabic qahwa, a truncation of qahhwat al-bun meaning wine of the bean.
-The first coffee house was opened in 1471 in Istanbul and was called Kiva Han. The first European coffee house was opened in Italy in 1645.

-At first coffee was mostly grown in Ethiopia where it was cultivated by highlanders.

Caffeine molecule 

The perfect espresso requires 42 coffee beans.

Chemical Structure of Caffeine 

How much caffeine is in there? 

Amount of caffeine in one average cup (200 ml/7 oz):

Brewed coffee: 60-130 mg
Instant coffee: 65-100 mg
Decaf coffee: 2-5 mg
Black tea: 40-50 mg
Green tea: 15-25 mg
Hot chocolate: 3 - 35 mg

Shot of espresso (30ml/1oz) contains 25-30 mg caffeine

Red Bull Energy Drink (250 ml/8.3 oz): 80mg
Can of Cola (350 ml/12 oz): 35-45 mg

Dark chocolate: (100 g/3.3 oz) 66 mg
Milk chocolate: (100 g/3.3 oz) 20 mg

“Coffee is a beverage that puts one to sleep when not drank.
-Alphonse Allais”

Prepared by adding espresso into hot water. Strength is similar to drip coffee, but flavor is different0 points

Consists strong coffee (or espresso) with scalded milk.0 points

MARIE CURIE Physicist, Scientist Born in 1867 , died in 1934

Marie Curie was born Marya Salomee Sklodowska (sklaw DAWF skah) in Poland when that part of the country was under Russian rule. She was the youngest of five children. She had a brother and three older sisters.

When she was four years old one of her older sisters taught her the alphabet, and Manya (as they called her) learned how to read. In fact, she could read better than Bronya who had taught her.

Her father was a professor. Sometimes the family would rent out rooms to students to help pay the bills. At one time they had ten boys living in the apartment with the family, and Manya had to sleep on a couch in the dining room.

Her mother was very ill with tuberculosis* and died of the disease when Manya was ten years old.

When she graduated from high school she won a gold medal because she had been such a good student. Her father knew she had worked very hard, and as a reward, she was permitted to spend a whole year in the country with relatives. She enjoyed a marvelous year with her cousins.

She wanted to study when she returned to Warsaw, but there was no money to send her away to college. She and her sister did private tutoring to earn money. Manya told her sister she would work to send her to school, then when Bronya became a doctor, she could return the favor. That's what they did.

Marie became a governess to a family in the country and also had an opportunity to teach several peasant children to read and write.

She fell in love with her employer's son, but his parents thought she wasn't rich enough or good enough to marry their son.

Her sister invited her to come to Paris to live and begin her studies. Manya changed her name to a French name, Marie. At the Sorbonne, the university, she chose to study mathematics and physics. While studying there she lived in a cold apartment and survived on very little food, but when she graduated she had the highest grades in the class. She had a master's degree in physics. Then she was awarded a scholarhip and was able to study further to get a master's degree in mathemetics. She would also later receive a doctorate in physics.

She met Pierre Curie and they married in 1895. With the money a cousin gave her for a wedding present, Marie bought two bicycles, one for herself and one for Pierre. They pedaled through the French countryside on their honeymoon.

Marie and Pierre in the laboratory

Pierre and Marie began experimenting together and discovered two new radioactive elements. She named one of them polonium* to honor her native country Poland, and the other they named radium* . They worked four years preparing a very small quantity of radium in order to prove there really was such an element. They had to work with a ton of pitchblende* uranium ore to accomplish this. The Austrian government had provided the ore, and they only had to pay for transporting it. Marie worked hard carrying very large jars of liquid during those years of experimenting.

In 1903 Pierre and Marie along with Henri Becquerel (ahn REE beck REL) received the Nobel Prize* in physics for their work and their discovery of radioactivity* . The money they received made life a little easier, and they also used some of it to help friends and family members. In 1911 she was again awarded the Nobel Prize for discovery of the two new elements polonium and radium.

The Curies had two daughters, Irene and Eve. They were good, loving parents. Pierre was offered a professor's job at the Sorbonne. Life seemed to be getting easier for them.

Then the unthinkable happened; Pierre was killed when he stepped out in front of a wagon being pulled by horses. Marie was in shock. What would she do without him? She felt like only half a person with Pierre gone, but she was strong and able to continue their work. They let her start teaching his classes at the Sorbonne. She was the first woman to teach at the university. Pierre's father, Dr. Curie lived with the family and helped to raise the girls. Four years later, he too died.

During the First World War Marie determined she could best serve by outfitting some cars with x-ray machines which could be taken to the battlefield hospitals. Bullets and shrapnel* could be located with x-rays to help the doctors treat the wounded soldiers. Irene, who was seventeen years old, helped her mother by becoming a nurse and working with her on the battlefield. Marie trained 150 women to become x-ray technicians.

Madame Curie made two trips to America to receive a gram of radium each time, first from President Warren Harding and eight years later from President Herbert Hoover.

In 1923 the French government gave her a pension of 40,000 francs a year in recognition of her lifetime of work in France.

She became ill and died from all her years of exposure to radium. Today doctors identify the disease as leukemia.

After Marie's death her daughter Irene and her husband Frederic Joliot received the Nobel prize for their work in atomic research. She followed in her mother's footsteps to also become a great scientist.

Many people have benefited from the discoveries made by Pierre and Marie Curie. The radiation which burned their skin as they worked with it, eventually came to be used to kill cancer cells in patients suffering from the disease.

Nobel Gas NEON

Interesting facts about neon

The Noble Gas neon is one of the most inert elements known. Finding interesting facts about an element that does not do very much is difficult but I’ll try.

Starting with the elements basic properties, its atomic weight is 20.1797 and its density 0.0008999 grams per cubic centimeter. The ionization energy of neon is 21.565 eV and its oxidation state is 0.

Within the periodic table, neon occurs in period 2 and group 18. All group 18 elements have a complete outer shell of electrons. This configuration is very stable so they do not readily form compounds with other elements.

The scientists Sir William Ramsay and Morris M. Travers discovered the element in their studies on liquid air in 1898. During these studies, the pair also discovered two other noble gases - xenon and krypton. They named their newly found element after the Greek word “neos” meaning new.

Within the Earth’s atmosphere, neon occurs at a concentration of only 1 part in 65000. Despite this low concentration, commercial neon production is by the fractional distillation of liquid air. This process also produces the noble gases krypton, xenon and argon. Although rare in the Earth’s atmosphere neon is the fourth most abundant element in the universe. Naturally occurring neon consist of three stable isotopes neon-20, neon-21 and neon-22.

With a melting point of minus 248.59 C (24.56 K, minus 415.46 F) and a boiling point of minus 246.08 C (27.07 K, minus 410.94 F) liquid neon is of value as a liquid refrigerant. It has 40 times more refrigerating capacity than the more expensive liquid helium and more than 3 times that of the more explosive liquid hydrogen.

Within a discharge tube, neon exhibits a bright red glow. All the naturally occurring noble gases glow within discharge tubes but neon produces the brightest light at normal wattage and current. This ability has led to its major use in the world of advertising as it lights many an illuminated advertisement hoarding.

Of the compounds of neon very little can be said. It forms an unstable hydrate and possibly a compound with the highly reactive element fluorine.  An electrical discharge will cause neon to combine with mercury vapor. Van der Waal’s forces then hold this mercury-neon product together. Optical and mass spectroscopic analysis has revealed the presence of the following ions Ne+, (NeAr)+, (NeH)+ and (HeNe+).

Natural Mosquito Repellent Safety

It's easy to make your own natural mosquito repellent. You can control exactly what goes into the product so you won't need to worry about any unwanted chemicals.

Natural Mosquito Repellent Safety

There are a couple of different formulations you can make for your natural mosquito repellent. In general, what you are doing is diluting an essential oil that the mosquitoes find distasteful or which confuses them so they can't find you to bite you. The oils don't mix with water, so you'll need to add them to other oils or to alcohol. It's important to use an oil or alcohol that is safe for your skin. Also, don't go overboard with the essential oils. The oils are potent and could cause skin irritation or another reaction if you use too much. If you are pregnant or nursing, do not use any mosquito repellent, natural or otherwise, until after you've gotten it cleared by your physician.

Natural Mosquito Repellent Ingredients

If you are making large amounts of mosquito repellent, a good rule of thumb is to mix the repellent so it's 5-10% essential oil, so mix 1 part essential oil with 10-20 parts carrier oil or alcohol. For a smaller batch use:

• 10-25 drops (total) of essential oils
• 2 tablespoons of a carrier oil or alcohol

The essential oils that work well against mosquitoes are:

• cinnamon oil
• lemon eucalyptus oil
• citronella oil
• castor oil

Safe carrier oils and alcohols include:

• olive oil
• sunflower oil
• any other cooking oil
• witch hazel
• vodka

Natural Mosquito Repellent Recipe

Mix the essential oil with the carrier oil or alcohol. Rub or spray the natural insect repellent onto skin or clothing, using care to avoid the sensitive eye area. You'll need to re-apply the natural product after about an hour or after swimming or exercise. Unused natural insect repellent may be stored in a dark bottle, away from heat or sunlight.