Where does kerosene come from?

Kerosene Lamp

Kerosene is a kind of oil that is used as a fuel for jet engines and for burning in lamps and in stoves—especially camping equipment—for lighting or cooking.

Most kerosene comes from petroleum, the oil that comes from oil wells.

Petroleum is a mixture of many materials.  Separating petroleum into its many parts is called refining” it.

At an oil refinery, the petroleum is heated until the kerosene part changes into a vapor.  The hot kerosene vapor is drawn off and condensed back into its liquid form.  The kerosene is processed to make it pure.

Other fuels, such as gasoline and diesel oil are refined from petroleum in the same manner as kerosene.

Petroleum also provides oil and greases for machinery lubrication and asphalts for paving highways.

Kerosene is often called “coal oil” because kerosene was first obtained by refining the oil from coal.

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What is the earth’s atmosphere?

You and I live at the bottom of a great ocean of air that surrounds the earth and that extends upward for hundreds of miles.  We call it to the atmosphere.

We could not live without it and the oxygen it contains.

It keeps the earth’s temperature from becoming too hot or too cold.  It also keeps out some harmful energy from the sun.

The atmosphere is made up mostly of nitrogen and oxygen.  But theirs are arise small amounts of other gases present, too.

There is always some water vapor and dust in it, too.

The earth holds the atmosphere to it by the pull of gravity, otherwise it would drift off into space.

The atmosphere is made up of different layers.  The bottom one, the troposphere, holds most of the air living things breathe.

The higher above the earth you go, the thinner the atmosphere becomes until it gradually fades into interplanetary space.,

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Do identical twins have the same fingerprints, handprints, and footprints?

Identical Twins

Do identical twins have the same fingerprints, handprints, and footprints?

Identical twins are genetically the same—but the laws of genetics don’t completely determine physical appearance.  The prints of identical twins are more alike than the prints of two completely unrelated people—but they’re still not identical.

Each one of us started out as a fertilized eggs.  In the case of identical twins, two people arose from the same egg.  After the egg was fertilized, it split in two—so identical twins are of the same sex.  They often have nearly the same height, weight, and hair color.  But look closer and you’ll find differences in twins—in birthmarks, motes, hair patterns, and teeth development.

Source:  http://ask.yahoo.com/ask/20010213.html

 

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How does a smoke deterctor work?

Smoke Detector

Every modern business building nowadays is equipped with smoke detectors (also known as smoke alarms) that have the potential to save millions of lives at very little cost.

The little contraption consists of two basic parts:  a sensor (to detect smoke) and an electronic audible alarm (to rouse people up).  We’ll look into how an optical (photoelectric) smoke detector works.

Have you gone to a place where the glass door automatically opens just before you step inside the building?  The system consists of a light source and a sensor on the other side.  What happens is, when you cross the beam of light, you block it.  the photodetector senses the lack of light and triggers a mechanism that opens the door.

For smoke detectors, however, there is a slight modification.  This type of detector includes a light source, a lens to collimate the light into a beam and a photoelectric sensor at right-angles to the beam.

In the absence of smoke, the light passes in front of the detector but does not fall on it.  when visible smoke enters the beam, some light is scattered by the smoke particles, and some of the scattered light is detected by the sensor.  An increased output from the sensor sets off the alarm.

The other type of smoke detector is the ionization detector that uses radioactive material to detect smoke produced by flaming fires. 

Sources

How Smoke Detectors Work.  http://home.hoswtuffworks.com/smoke/htm

Smoke Detector.  http://en.wikipedia.org/wiki/Smoke_detectors

How can you make oil sink in water?

Lava Lamps

An object will float or sink in a liquid, depending on its density.  Density is a property of matter that tells us how heavy something is for its size. 

For oil and water, liquids deemed to be immiscible.  But still, oil can sink in water.  How?  There are several ways.  One, you can opt for oils that have higher density.  Two, you may choose to apply heat to oils with low coefficient of expansion.  As you heat the water, its density will decrease whereas the density of the oil will more or less remain the same.  The oil will sink as soon as the water’s density decreases to its lowest point, well before it boils.  Lastly, you can mix the oil of your choice with an ingredient that cann increase its density.  The same principle works for saltwater.  The reason it is denser than freshwater is due to its salt content

Lava Lamps

Lava lamps, or liquid motion lamps were invented by Craven Walker in 1964.  Filled with liquid and a special kind of colored wax, this lamps glows when the bulb, set at the base, is switched on.  The bulb heats and melts the wax, causing it to float to the top of the lamp.  When it cools, it sinks to the bottom, and this cycle is repeated over and over.

Sources

► www.physlink.com/Education/AskExperts/ae705.cfm

► www.exploratorium.edu/science_explorer/volcano.html

 

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What is the difference between a hill and a mountain?

A hill or a mountain is a part of the land that is higher than the land around it.  While a mountain is generally thought of as being much larger than a hill, there is actually no clear-cut difference between them. 

The word “mountain” means different things to different people.  Wheat is called a mountain in one region may be considered only a hill by people living in a more rugged part of the world. 

The Turtle mountains which rise from the flat plains of North Dakota, for example, are considerably smaller than the Black Hills of South Dakota. 

Although there is no precise difference between a hill and a mountain, most geographers, by general agreement, define a mountainous area as one that lies at least 2,000 feet above its surroundings. 

Its land surface consists of high, narrow ridges, long slopes, and deep canyons or valleys.  The region, will also include two or more zones of climate and plant life.

How does a sundial tell time?

Sundial

Long before we had clocks and watches, people used sundial to tell time.  A sundial is really a shadow clock – it tells the time by the sun’s shadow. 

A sundial consists of the dial face and the gnomon (pointer), which is set in the center of the dial.  The dial is divided into hours. 

Many sundial have dials numbered in Roman numerals from 5 to 8.  When the sun strikes the gnomon, it casts a shadow that points toward the numbers on the dial.  As the sun moves across the sky during the day,  the time is told by the shadow of the gnomon falling on the different numbers. 

A sundial cannot tell the time at night when the sun is not shining, nor can it tell the time when the sun is hidden by the clouds.  And it cannot rely time by minutes and seconds.  It is no, wonder that people worked out other ways of telling time. 

Today, sundials are often built in gardens for their looks rather than for their usefulness.

 

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Why does a fire smoke?

Fire and Smoke

We’ve all see smoke rising from a bonfire or the chimneys of factories and houses. 

When a log in a fireplace burns, some of the burning wood is changed into invisible gases.  These hot gases, which consist mostly of water vapor and carbon dioxide.  Are very light.  They rise up the chimney and drift away with the air. 

If burning were complete we could not see the hot gases, but usually many tiny bits of ash and black specks of unburned fuel (know as soot) are also carried away in the rising clouds of gases.  The soot and ash color the gases gray or almost black and make them visible in the form of smoke.  Some soot sticks to the flue of the chimney, blackening it. 

The chimney does more than just carry off the smoke.  As the column of hot gases rises up the chimney it causes a draft that draws air into the fire.  This causes the fire to burn hotter and smoke less. 

Visual source:  asksabre