Why is every snowflake different?

Modern physics has made great progress toward explaining the genesis of the snowflake's form. Its hexagonal symmetry has its origin in the shape of a water molecule, which consists of an atom of oxygen and two atoms of hydrogen. They are connected in such a way that the hydrogen "arms" make an angle like the arms on the letter x. This angle ensures that when the water molecules link to form a crystal, the resultant symmetry will be hexagonal. Regarding the probabilities of combination, a single snow crystal consists of something like one quintillion molecules of water. The number of ways that many molecules can be arranged into six-sided crystals is astronomical. So the odds are huge that no two snowflakes have ever been exactly alike.

Last 7 Days

What is the full definition of sunrise and sunset?

The point on the celestial sphere directly above an observer is called the zenith. The great circle on this sphere exactly 90 degrees in every direction from the zenith is called the (astronomical) horizon. If the observer is on a flat surface, like the ocean, and has his or her eye on the surface, sunrise or sunset occurs when the upper edge (called upper limb) of the Sun disk intersects with the horizon. Realty is a bit more complex. Light passing through the atmosphere is refracted and bent downward, giving the observer the impression that the object is higher in the sky than it really is. The nearer the object is to the horizon, the larger it appears. When the lower limb of the Sun appears to touch the horizon, the Sun has already gone below it because the refraction "lifts" the Sun by more than the diameter of the Sun disk. Of course, all this means nothing if you happen to live in the shadow of a mountain. Near where I live on the Ohio River is a small town by the name of Shadyside. A high hill on the western edge of town puts it in the shade of the hill hours before true, astronomical sunset.

Is it true that you can tell how high the snow will be by looking at how high the bees build their nests?

There's an old saying, "When hornets build their nests near the ground, expect a cold and early winter." We haven't heard one about bees but think the same saying could apply.

Why is salt used to melt snow?

The weight of the salt crystals provides a pressure that melts the snow. Once melted the salt dissolves in the water melt, preventing it from freezing. The drier winter air evaporates this water melt.

What is the difference between a tornado and a typhoon?

The difference lies in their size, wind velocity, rate of travel, and duration. A tornado reaches rotating speeds up to 300 miles per hour, travels between 25 and 40 miles per hour, and generally lasts for a few minutes (although it can exist for hours). A typhoon (the term used in the Pacific for a hurricane) has winds that vary from 75 to 200 miles per hour, moves between 10 and 20 miles per hour, has a diameter up to 600 miles, and exists from days up to a week. A tornado generally forms several thousand feet above Earth's surface, usually during warm, humid weather. A typhoon breeds in low-altitude belts over the ocean, generally from 5 to 15 degrees latitude north or south.

I have noticed that the cicadas have started singing early this year. What is the relationship between the cicadas' singing and our weather?

Weather folklore says that cicadas start singing six weeks before a frost -- so it looks as though you may be seeing an earlier than usual frost this year. The bright side is that folklore also says that the singing of cicadas heralds warm, dry days ahead. We recommend enjoying those warm, dry days while you can!

Is there any proof that the asteroids between Mars and Jupiter were once a planet?

There was a time when astronomers thought that the asteroids were the remnants of a shattered large planet. Today, scientists believe the asteroids are clumps of matter which never made it to a bigger planet.

Where did the term southpaw come from?

This term was coined in 1891 to describe a left-handed baseball player, especially a pitcher. Eventually, its usage spread to all left-handed people.

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