ARGH, so much cluelessness on science in this thread.
Things CONTRACT when they freeze, because they are becoming more dense.
Water is a complete exception to the rule. The reason is the atomic structure of water. If you've ever seen one of those Mickey Mouse hats, that's actually a pretty good picture of a water molecule: big central sphere, 2 smaller ones going off at right angles. Effectively, each water molecule looks like a capital L.
Now, when it's in a liquid state, all of those L's are jumbled together and can thus fit together tightly. Indeed, the colder water gets, until 4 degrees Celcius, those molecules fit closer and closer together, and water gets more and more dense. It's not a HUGE amount of increase, but yes, water at 4 degrees is more dense than room temperature water.
However, once water gets colder than 4 degrees, it starts displaying a crystaline structure, and all of those L-shaped molecules start lining up like this:
LLLLLLLLLLL
LLLLLLLLLLL
LLLLLLLLLLL
LLLLLLLLLLL
LLLLLLLLLLL
Now, obviously, when the molecules are lining up like that, it leaves lots of empty and open space between each molecule, so it now becomes les dense and expands again. This is why ice floats; all the empty spaces between the molecules that have lined up in the crystaline structure.
But, again, it is that special shape of water molecules that causes this situation. Other substances do not necessarily do so, and thus will conform to the usual laws of density, which is: solid > liquid >>>>> gas.
-Arlos
Expanding ~ hot or cold?
Moderator: Dictators in Training
Last edited by Arlos on Wed Aug 16, 2006 2:13 pm, edited 1 time in total.
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Trielelvan
- NT Traveller
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Markarado wrote:Thanks NTers, you're all the best!
So is it true that feet, inches, etc.. actually come from England?
No.
In ancient times, the body ruled when it came to measuring. The length of a foot, the width of a finger, and the distance of a step were all accepted measurements.
Inch: At first an inch was the width of a man's thumb. In the 14th century, King Edward II of England ruled that 1 inch equalled 3 grains of barley placed end to end lengthwise.
Hand: A hand was approximately 5 inches or 5 digits (fingers) across. Today, a hand is 4 inches and is used to measure horses (from the ground to the horse's withers, or shoulder).
Span: A span was the length of the hand stretched out, about 9 inches.
Foot: In ancient times, the foot was 11 1/42 inches. Today it is 12 inches, the length of the average man's foot.
Yard: A yard was originally the length of a man's belt or girdle, as it was called. In the 12th century, King Henry I of England fixed the yard as the distance from his nose to the thumb of his out-stretched arm. Today it is 36 inches.
Cubit: In ancient Egypt, a cubit was the distance from the elbow to the fingertips. Today a cubit is about 18 inches.
Lick: A Lick was used by the Greeks to measure the distance from the tip of the thumb to the tip of the index finger.
Pace: The ancient Roman soldiers marched in paces, which were the length of a double step, about 5 feet; 1,000 paces was a mile. Today, a pace is the length of one step, 2 1/2 to 3 feet.
10sun wrote:10sun wrote:Hey guys, what does a meter represent?
In 1791, the French Academy of Sciences defined meter is one ten-millionth of the length of the earth's meridian along a quadrant (one fourth the circumference of the earth).
Then in 1983, The General Conference on Weights and Measures defined a meter as the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. The speed of light is 299 792 458 m/s.
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Darcler
- Saran Wrap Princess
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We finally have a freezer that has an ice maker, after living in apartment after apartment, its nice to have something nice and new. But it makes those big long ice cubes and I like those smaller round ice cubes that fit in your mouth easier without touching your teeth. I have cold sensative teeth.
I eat a lot of ice. Sonic and hospital ice FTW!!!!
I eat a lot of ice. Sonic and hospital ice FTW!!!!