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Where was the sun in Ptolemy's model of the universe?

The Ptolemaic model placed each celestial body on another ring, called the epicycle, which centered on the deferent, to explain observed retrograde motion. The geocentric properties of Ptolemy's model are similar to the models proposed by Plato and Aristotle and the first heliocentric models created by Copernicus used the Ptolemaic model's deferents and epicycles.

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Where do nutrients enter the blood?

The body uses various nutrients, including fats, proteins, carbohydrates, water and vitamins. Most nutrients enter the system via the foods and beverages a person ingests. Enzymes in saliva begin the process of digestion, which continues in the stomach and intestinal tract and by additional enzymes from organs, such as the kidneys and liver, to break down foods and beverages into component molecules that are either absorbed for nutrients or passed out as waste in feces or urine. The bloodstream receives absorbed nutrients primarily through the small intestine, where the final stage of hydrolys..

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What is the balanced equation for the complete combustion of heptane?

A combustion reaction is generally defined as a reaction with atmospheric oxygen that produces carbon dioxide and water. A balanced equation ensures that the same amount of atoms are present on both sides of the equation. The numbers in front of each component of the reaction indicate the number of each molecule present. For the combustion of heptane, one molecule of heptane and 11 molecules of oxygen produce seven molecules of carbon dioxide and eight molecules of water.

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How can you tell if something is real silver?

Silver is not attracted to magnets, so a small piece of the metal is not moved by a bigger magnet. Similarly, a small magnet does not stick to a larger silver object. Finally, silver seems to make ice melt at a faster rate than it typically does when out of the freezer. The metal is a good conductor of heat, so the melting process speeds up when an ice cube is placed on a piece of silver.

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Do feet keep growing?

A woman may gain as much as a half-inch size in shoes during pregnancy, reports Maine Senior Guide. This increase is based on swelling and pressure from the weight of the pregnancy. The aging process affects the size of a person's foot. Later in life, the pressure placed by the body on weak foot muscles and ligaments causes stretching and thinning of fat pads on the bottom of the foot, according to the Los Angeles Times.

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Where do cysts come from?

The word "cyst" comes from the Latin word cystis, which means "bladder" or "pouch". A cyst is essentially a pocket of tissue that may contain trapped air, fluid, or other bodily substances. Most cysts are benign, or non-cancerous. According to WebMD, most cysts are not painful, do not cause problems or require treatment, and go away on their own. At home, applying pressure with a warm compress helps speed the drainage and healing process. Some cysts, however, can grow quite large and become uncomfortable or painful. Cysts may also become infected, inflamed, or ruptured. In these cases, profess..

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What is the solubility of biphenyl?

Biphenyl is a very nonpolar type of molecule, and a reason behind this is that it bonds to itself through nonpolar van der Waals interactions. This is why it cannot mix well with water, which is a polar molecule. Polar and nonpolar molecules do not mix. This is why nonpolar molecules like biphenyl are referred to as hydrophobic, which means they do not interact well with water.\nAccording to research conducted by the Oral Roberts University, biphenyl was found to be soluble in a number of organic solvents, however. Some of these solvents included 1,2-dibromoethane, 1,2-dichloroethane, 1-butano..

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What are the elements of weather?

The temperature element is the numerical measure of air in the atmosphere. Temperature is found using a thermometer and can be in Fahrenheit or Celsius. The temperature of the air has an effect on the rate of evaporation in the atmosphere, the amount of humidity and what form precipitation is in. Any state of water that falls from the sky is defined as "precipitation." This can be rain, sleet, snow or hail.\n"Humidity" is defined as how much water vapor is in the air. The state in which water is a gas is defined as "water vapor." Humidity is used to predict the chances of precipitation, dew or..

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Which type of blood cells carry waste away from cells?

Red blood cells are the type of blood which carry waste product from the cells, in the form of carbon dioxide, to the lungs. The waste is then removed from the cells of the body, and brought to the lungs to be released during exhalation (or breathing out). Red blood cells also bring oxygen from the lungs to the cells, so that they are refreshed. They are a very important component within the body. That is why there are so many in blood — in fact, there are 5 million red blood cells in just one drop of blood.

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What effect did Mount St. Helens have?

Native Americans living in the area before the first Europeans crossed the United States to the area presently known as Washington State recognized the fiery potential of the mountain. However, a period of dormancy from 1857 until the 1980 eruption had led people to lay aside any fears of the mountain. The homes they had built at the base of the volcano were destroyed when the volcano erupted. In addition, the eruption caused serious economic hardship for many in the area.\nThe eruption began with an earthquake that also started an avalanche. In just minutes, rock and debris traveled into Spir..

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