Comets are solar system bodies that orbit the Sun, just as planets do, except a comet usually has a very elongated orbit. Part of its orbit is very, very far from the Sun and part is quite close to the Sun. They are sometimes nicknamed dirty “cosmic snowballs,” because they are small, irregularly shaped chunks of rock, various ices, and dust.
As the comet gets closer to the Sun, some of the ice starts to melt and boil off, along with particles of dust. These particles and gases make a cloud around the nucleus, called a coma. The coma is lit by the Sun. The sunlight also pushes this material into the brightly lit “tail” of the comet.
Early bicycle tires were made out of solid rubber. (Before that, iron covered the edges of wooden bicycle wheels.) Solid rubber tires made bicycling a bumpy experience because they were unable to provide any cushioning on rough roads. When the airfilled rubber bicycle tire was invented, it made riding a lot more comfortable. But along with the comfort of air-filled tires came the frequent task of filling them up. The rubber that is used to make bicycle tires is thin and porous, which means that it has tiny microscopic pores, or holes, through which air can escape over time.
Air that is pumped into bicycle tires is pressurized, meaning it is compressed into a much smaller space than it would ordinarily occupy. Without pressurized air inside, a bicycle tire would not have its firm shape. Air under high pressure, like all gases, moves or migrates to surrounding areas that have lower pressure, traveling even through fairly solid materials. Air in a bicycle tire naturally tries to escape through the valve stem that is used to fill it and the inner tube that holds it. So even bicycles that don’t undergo the wear-and-tear of frequent use eventually end up with flat tires.
Today’s computers contain millions of transistors placed in a tiny piece of sili- 162 con, some so tiny that they can fit in an ant’s mouth. The transistors (devices that control the flow of electric current) are packed and interconnected in layers beneath the surface of the chip, which is used to make electrical connections to other devices. There is a grid of thin metallic wires on the surface of the chip.
This silicon chip was independently co-invented by two American electrical engineers, Jack Kilby and Robert Noyce, in 1958–1959. The chip, along with the invention of the microprocessor, allowed computers to get smaller and more efficient. Silicon chips are also used in calculators, microwave ovens, automobile radios, and video cassette recorders (VCRs).
The surface of a liquid is the seat of a special force as a result of which molecules on the surface are bound together to form something like a stretched membrane. They tend to compress the molecules below to the smallest possible volume, which causes the drop to take a round shape as for a given mass he sphere has minimum volume.
In the early days of theatre, the players were lit by gas lamps hidden across the front of the stage. Early in the twentieth century, it was discovered that if a stick of lime was added to the gas, the light became more intense, and so they began to use the “limelight” to illuminate the spot on stage where the most important part of the play took place. Later called the “spotlight,” the “limelight” was where all actors fought to be.
Yes and no. Bones are hard connective tissue, made up of bone cells, fat cells, and blood vessels, as well as nonliving materials, including water and minerals. Some bones have a very hard, heavy outer layer made out of compact bone. Under this layer is a lighter layer called spongy bone, which is located inside the end, or head, of a long bone.
Spongy bone is tough and hard, but light, because it has lots of irregularly-shaped sheets and spikes of bone (called trabeculae) that make it porous (full of tiny holes). The soft, jelly-like inner core of bone is called the bone marrow. It is where red blood cells, certain white blood cells, and blood platelets are formed. The jawbone is the hardest bone in your body. Although bones are hard, they are not the hardest substance in the human body: the enamel on your teeth is harder.
Chocolate contains a range of nutrients which include minerals such as potassium, calcium and iron. It also contains the B-vitamin riboflavin. It is true that most of chocolates’ calories do come from fat but the ingredient, known as cocoa butter, is the kind of fat that consists mostly of monounsaturated fatty acid also found in olive oil; the ‘healthy’ fat needed in all diets.
Although studies are constantly being done with chocolate (and why not?), studies in the past have shown two significant additional positives. In these test studies, the people who consumed cocoa regularly had a lower blood pressure than those that did not, were less likely to die from cardiovascular disease and had better peripheral blood flow.
Dark chocolate has the potential to have the largest quantity of cocoa solids – at least to 70%. This means that 70% of the chocolate is from the cocoa bean and less from added sugars, oils and perhaps other fillers. Thus the antioxidants in the dark chocolate surpasses pecans (14% less) and red wine (25% less).
Besides the wonderful benefits from our all natural chocolate, nuts are a great food. In general, nuts are loaded with protein. Peanuts have the most, followed by almonds, cashews and walnuts. Protein is essential for healthy brain and muscle function, and for vegetarians, are a great substitute for animal protein. Nuts also contain omega-3 fatty acids, antioxidants and fiber. Thus with all the added benefits of chocolate, chocolate dipped nuts are a great snack.
Guion S. Bluford Jr. became the first African American to fly in space during the space shuttle Challenger mission STS-8, which took place from August 30 to September 5, 1983.
He returned to space again in 1985 aboard Challenger mission STA-61-A/Spacelab D1. Mae C. Jemison became the first African American woman in space on September 12, 1992, when she flew aboard the space 18 shuttle Endeavour mission Spacelab-J.
Guglielmo Marconi, of Bologna, Italy, was the first to prove that radio signals could be sent over long distances. Radio is the radiation and detection of signals spread through space as electromagnetic waves to convey information.
It was first called wireless telegraphy because it duplicated the effect of telegraphy without using wires. On December 21, 1901, Marconi successfully sent Morse code signals from Newfoundland to England.
If there is “blackmail” then there must be “white mail.” Mail was a Scottish word for rent or tax, and during the reign of James I, taxes or mail were paid in silver, which, because of its colour, was called “white mail.” During the sixteenth and seventeenth centuries, bandits along the Scottish border demanded protection money from the farmers. Because black signified evil, this cruel extortion was called a black tax, or “blackmail.”