Information Generator

This thread has the potential to be educational and fun if it catches on. Sadly, I doubt it will. But I'll try anyway. I've had this idea simmering in my mind for a few days and it keeps seeming better and better.

Reason

I often find myself asking questions about the world. Things that, for some reason, just never occurred to me before to ask. I'll usually Google for the answer and then my curiosity is quenched.

It's occurred to me that there might be additional benefit to answering questions that others have come up with, because you may end up seeking answers to interesting questions that never would have normally crossed your mind. It might also be fun to ask a question and have it answered concisely in one place, without having to do any work.

Rules

Ask a question about the world. It should be something you don't already know the answer to. Valid questions might be:

• Why is the sky blue?
• How many languages are there in the world?
• What are house cats descended from?
• What raw materials is plastic made out of?

The next person to reply must answer the question, and then post a question of his or her own. If you already know the answer to someone's question, feel free to answer based on it. If you don't, find the answer with the magical answer-generating device called the internet.

Two final rules

1. The question should not deal with subject matter in any extremely specialized area. The average person needs to know what it is you're asking.
2. The answers should be relatively short, maybe 1-10 sentences long. Don't ask a question that you think an extremely long answer will be required for. If the answer to a question you wish to respond to is complicated, provide a simplified version of the answer, or simply explain that the question is too complicated.

EDIT: It seems everyone is including a source, and that's a good idea, so it might as well be made a rule.

My question:
Why do deserts have sand?

Ok I'll go first.

Why do deserts have sand?

Quote:

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Sand is brought into a desert by wind, often from a nearby area of eroding sedimentary rock, like sandstone. At the same time, the dryness and winds of the area destroy most vegetation and soil, leaving only sand and rocks. It's important to remember, however, that not all deserts have sand, and that the presence of sand dunes doesn't mean that it's a desert. Antarctica, for example, is a desert because of the lack of precipitation.

Read more: Why are deserts made of sand? | GreenAnswers

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(I lifted the answer by the way from a site called Green Answers)

Now my question:

Why do men have nipples?

Why do men have nipples?

Quote:

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The answer is that as embryos men and women have similar tissues and body parts. If anything the embryo follows a 'female template'. That is why nipples are present in both sexes. It is the effect of the genes, the Y chromosome and the hormone testosterone that brings about the changes and masculinises the embryo. Testosterone promotes the growth of the penis and testicles. Because nipples are there before this process begins the nipples stay!

Read more: Why Do Men Have Nipples?

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My question:
Why do people and animals yawn?

Why do people and animals yawn?

Quote:

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Scientists don’t completely understand why people, or animals for that matter, yawn. However, It’s widely assumed that yawning occurs because we are tired or bored or because we see someone else doing it, but there isn’t any hard evidence to support these beliefs. Scientists speculate that the onset of a yawn is triggered either by fatigue, or by sheer boredom as, at those times, breathing is shallow, and little oxygen is carried to the lungs by the oxygen-toting cardiovascular system. When one yawns, his or her alertness is heightened, as the sudden intake of oxygen increases the heart rate, rids the lungs and the bloodstream of the carbon dioxide buildup, and forces oxygen through blood vessels in the brain, while restoring normal breathing and ventilating the lungs.

Read more: Why do we yawn?

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Question: Who invented the band-aid?

Q: Who invented the band-aid?

A: Earle Dickson, a cotton buyer, invented it in 1921. He noticed that his wife frequently cut herself while preparing food to cook. The regular bandages used at the time were made of separate gauze and adhesive tape, and would fall off of her fingers too easily. So he made his own out of gauze, duct tape, and crinoline (for sterility) which worked much better. His boss decided to manufacture band-aids based on his idea, and Earle was made Vice President of the Johnson & Johnson company.
Source: History of the Band-Aid

How many species are there in the world?

How many species are there in the world?

Quote:

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The number of known species is continually in flux as new species are found, taxonomic categories adjusted, and redundancies recognized. Compounding the problem is the fact that diversity is not evenly distributed across species, regions, or the planet. Seventy percent of the world's species occur in only 12 countries: Australia, Brazil, China, Columbia, Ecuador, India, Indonesia, Madagascar, Mexico, Peru, and Zaire. Current estimates of the total number of species on Earth range from 5 to 30 million, of which, the 2005 Millennium Ecosystem Assessment notes approximately 2 million have been formally described.
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Some species, such as many large mammal, butterfly, bird, plant, and insect species, have been well studied. Over half of all described species are insects, including nearly 300,000 known beetles. However, the estimated number of insects on Earth is thought to be close to 8 million and, proportionally, scientists are closer to naming all plant and vertebrate species. Little continues to be known about the distribution and biology of vast numbers of species groups, including arthropods, fungi, and nematodes.

Read more: The Environmental Literacy Council - How Many Species are There?

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What is the largest and fastest spider in the world? Not even sure I want to know the answer. :P

What is the largest and fastest spider in the world?

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There actually multiple spiders which fit these different categories. There is not a single spider that is both the largest and fastest.

The world's largest spider in terms of mass is the Goliath Birdeater, which gets its name from explorers in the victorian era where one explorer witnessed one eating a humming bird. A Goliath Birdeater can weigh over 170g and can have a legspan over 30cm. A Goliath Birdeater's diet usually consists of large insects but they are know to eat lizards, birds, bats and even venomous snakes. Luckily, they are relatively harmless to humans. :3

Read more: Goliath Birdeater Tarantula
Picture: Goliath Birdeater

The world's largest spider in terms of leg span is the Giant Huntsman spider which is known to have a leg span of over 30cm. Their species is known to feed on insect pests and are relatively harmless to healthy humans which is why many people who live in tropical places will actually relocate these spiders to their gardens, rather than kill them.

Read more: Sparassidae
Picture: Giant Huntsman Spider

The fastest spider in the world is actually the Giant House Spider, which can run 330 times its own length in 10 seconds. In proportion to its size, this spider is actually faster than the cheetah. This spider can run at speeds of up to 0.53 m/s or 1.73ft/s.

Read more: Species Tegenaria gigantea - Giant House Spider
Picture: Giant House Spider

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What is the world's spiciest substance?

What is the world's spiciest substance?

Quote:

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First a definition. In 1912, Chemist Wilbur Scoville developed a scale to measure the hotness or "pungency" of peppers, and the result is the Scoville Scale, which ranks the hottest peppers and spices in the world.

Considering Bell peppers rank zero (0 SR) and Jalapeño peppers rank between 2,500 and 8,000 SR in Scoville heat units, the most piquant spice in the world measures in at 16,000,000 SR (yes, 16 million!).

We're talking a whole 'nother level of mouth-scorching heat.

United States

Who knew the spiciest edible substance on earth—8,000 times hotter than Tabasco sauce—was right in our backyard?

Blair's 16 Million Reserve is made of raw capsaicin, the chemical component found in most chili peppers around the world, and tops the Scoville chart at 16,000,000 SR.

Sold in a tiny vial, these crystals can cause fainting with a single sniff, and downing an entire bottle will most likely end your life. A single crystal is enough to spice up an entire pot of stew. Even a bowl of tepid oatmeal can become the spiciest breakfast on earth. (Got this from The World's Hottest Peppers—And Where to Eat Them | Travel News from Fodor's Travel Guides )

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What is the most poisonous animal in the world?

What is the most poisonous animal in the world?

Quote:

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It is really hard to tell which animal is the most poisonous in the world. The one that has the most toxic chemicals? The one that kills the biggest amount of people a year? Or maybe the one with the biggest amount of poison?
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The top prize for “The World Most Venomous Animal,” would go to the Box Jellyfish. It has caused at least 5,567 recorded deaths since 1954. Their venom is among the most deadly in the world. It’s toxins attack the heart, nervous system, and skin cells. And the worst part of it is that jelly box venom is so overpoweringly painful, that human victims go in shock, drown or die of heart failure before even reaching shore. Survivors experience pain weeks after the contact with box jellies.
You have virtually no chance to survive the venomous sting, unless treated immediately. After a sting, vinegar should be applied for a minimum of 30 seconds. Vinegar has acetic acid, which disables the box jelly’s nematocysts that have not yet discharged into the bloodstream (though it will not alleviate the pain). Wearing panty hose while swimming is also a good prevention measure since it can prevent jellies from being able to harm your legs.
Jelly box can be found in the waters around Asia and Australia.
Read more (top 10): 10 Most Poisonous Animals in the World | Village Of Joy

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How are northern lights formed?

How are northern lights formed?

Quote:

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The northern lights are much like meteors (falling stars), but is formed with billions of objects that are much faster and much smaller than the normal meteor that is seen on a clear night. It comes from solar wind; the highly charged particles that come from solar flares and other events on the sun that radiate outwards. Some of these particles are captured by Earth's magnetic field, due to the correlation of electric charge and magnetism, and keeping their speed, slam into the atmosphere, at the poles. The sudden increase of energy experienced by the air causes the release of photons. (light) An interesting aside is that some A/V equipment is affected by solar wind, so an analog TV or radio that suddenly reduces its clarity without outside interference might be caused by solar wind, and thus, the northern lights are more often than not active at that moment.

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How many dimensions are there, and how do they relate to each other?

How many dimensions are there, and how do they relate to each other?

Quote:

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http://www.youtube.com/watch?v=jI50H...eature=related

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How many genes are in the human genome?

an estimated 20,000-25,000

What is the most rarely seen bird native to North America? (I want to find it)

^ We need a source, mister!