"The usual answer is that it isn't any colour; it's "clear" or "transparant" and the sea only appears blue because of the reflection of the sky.
Wrong. Water really is blue. It's an incredibly faint shade, but it is blue. You can see this in nature when you look into a deep hole in the snow, or through the thick ice of a frozen waterfall. If you took a very large, very deep white pool, filled it with water and looked straight down through it, the water would be blue.
This faint blue tinge does not explain why water sometimes takes on a strikingly blue appearance when we look at it rather than through it. Reflected colour from the sky obviously plays an important part. The sea doesn't look particularly blue on an overcast day.
But not all the light we see is reflected from the surface of the water; some of it is coming from under the surface. The more impure the water, the more colour it will reflect.
In large bodies of water like seas and lakes the water will usually contain a high concentration of microscopic plants and algae. Rivers and ponds will have a high concentration of soil and other solids in suspension.
All these particles reflect and scatter the light as it returns to the surface, creating huge variation in the colours we see. It explains why you sometimes see a brilliant green Mediterranean sea under a bright blue sky."
Showing posts with label the qi book of general ignorance. Show all posts
Showing posts with label the qi book of general ignorance. Show all posts
Tuesday, 9 July 2013
Thursday, 28 February 2013
The QI Book of General Ignorance
Here's another quite interesting passage from the QI Book of General Ignorance:
Q: What's the largest living thing?
A: It's a mushroom.
And it's not even a particularly rare one. You've probably got the honey fungus (Armillaria ostoyae) in your garden, growing on a dead tree-stump.
For your sake, let's hope it doesn't reach the size of the largest recorded speciman, in Malheur National Forest in Oregon. It covers 890 hectares (2,200 acres) and is between 2,000 and 8,000 years old. Most of it is underground in the form of a massive mat of tentacle-like white mycelia (the mushroom's equivalent of roots). These spread along tree roots, killing the trees and peeping up through the soil occasionally as innocent-looking clumps of honey mushrooms.
The giant honey fungus of Oregon was originally thought to grow in separate clusters throughout the forest, but reseatchers have now confirmed it is the world's single biggest organism, connected under the soil.
Q: What's the largest living thing?
A: It's a mushroom.
And it's not even a particularly rare one. You've probably got the honey fungus (Armillaria ostoyae) in your garden, growing on a dead tree-stump.
For your sake, let's hope it doesn't reach the size of the largest recorded speciman, in Malheur National Forest in Oregon. It covers 890 hectares (2,200 acres) and is between 2,000 and 8,000 years old. Most of it is underground in the form of a massive mat of tentacle-like white mycelia (the mushroom's equivalent of roots). These spread along tree roots, killing the trees and peeping up through the soil occasionally as innocent-looking clumps of honey mushrooms.
The giant honey fungus of Oregon was originally thought to grow in separate clusters throughout the forest, but reseatchers have now confirmed it is the world's single biggest organism, connected under the soil.
Tuesday, 11 December 2012
Books
Once again it's time to tell you about some of the books I've been reading! to start off, The Qi Book of General Ignorance. It's the first book published by the makers of the TV show Qi (which I love, by the way!) It takes well-known bits of general knowledge and tells you that everything you know is wrong. It's a non-fiction book, written in the style of questions and answers. I loved this book! Really loved it. So interesting! It made me feel very clever and very stupid simultaneously. Clever because I was learning cool new facts, and stupid because so much of what I thought I knew is apparently wrong. There's a foreword by Stephen Fry, and Four Words by Alan Davies. They read as follows: Will this do, Stephen? I'd like also to share with you a more interesting extract:
Q: What's the loudest thing in the ocean?
A: Shrimps. Though the blue whale produces the loudest noise of any individual animal in the sea or on land, the loudest natural nosie of all is made by shrimps. The sound of the "shrimp layer" is the only natural noise than can "white out" a submarine's sonar, deafening the operators through their headphones. Below the layer they can hear nothing above it and vice versa. Hearing from below can only be accomplished by raising a mast up through it. The nosie of the collected shrimps amounts to an ear-splitting 246 decibels, which even adjusting for the fact that sound travels five times faster in water, equates to about 160 decibels in air; considerably louder than a jet taking off (140 dB) or the human threshold of pain. Some observers have compared to everyone in the world frying bacon at the same time. The nosie is caused by trillions of shrimps snapping their single oversized claw all at once. Snapping shrimps, members of the various Alpheus and Synalpheus species, are found in shallow tropical and subtrpoical waters. But it's even more interesting than it sounds. Video shot at 40,000 frames per second shows clearly that the noise occurs 700 microseconds after the claw has snapped shut. The noise comes from burst bubbles - not the shutting of the claw itself - an effect known as "cavitation". It works like this. A small bump on one side of the claw fits neatly into a groove on the other side. The claw is shut so rapidly that a jet of water travelling at 100 kilometres (62 miles) per hour squirts out, fast enough to create expanding bubbles of water vapour. When the water slows down and normal pressure is restored the bubbles collapse creating intense heat (as high as 20,000 degrees C), a loud pop and light - this last being a very rare phenomenon called sonoluminescence, where sound generates light. Shrimps use this nosie to stun prey, communicate and find mates. As well as ruining sonar, the sharp, hot intense noise makes dents in ships' propellors.
Isn't that just so cool? Science rules! I might share some more extracts in the future, cos it really is brilliant.
And now, The Great Gatsby, by F. Scott Fitzgerald. Yes, I know, I know, how can I not have read this before? I think I must be just about the only person in the world who didn't do this book at school, but nevermind. It's read now. And it was very good. Cynical, but sweet, wordy and wistful. It was somehow very joyful and very sad at the same time. It vividly conjured up a world that's gone and the twist at the end was a big surprise. A very well written book.
And finally, All the Pretty Horses, by Cormac McCarthy. Another great book. It's about two boys who saddle their horses and ride South into Mexico and have lots of misadventures. I found it a bit of a contradiction, because it's seemingly very rough and ready, and yet also very sophisticated. The simplicity and sparsity of the dialogue contrasts highly with the wordiness and fluidity of the narration. It's earthy and polished at the same time. I loved it, but I will admit it took me a while to get through it. It's not a light read. There is quite a bit of violence in it. It's also largely not in English. A fair amount of it is in Spanish, so a working knowledge of the language is beneficial to the reader!
Q: What's the loudest thing in the ocean?
A: Shrimps. Though the blue whale produces the loudest noise of any individual animal in the sea or on land, the loudest natural nosie of all is made by shrimps. The sound of the "shrimp layer" is the only natural noise than can "white out" a submarine's sonar, deafening the operators through their headphones. Below the layer they can hear nothing above it and vice versa. Hearing from below can only be accomplished by raising a mast up through it. The nosie of the collected shrimps amounts to an ear-splitting 246 decibels, which even adjusting for the fact that sound travels five times faster in water, equates to about 160 decibels in air; considerably louder than a jet taking off (140 dB) or the human threshold of pain. Some observers have compared to everyone in the world frying bacon at the same time. The nosie is caused by trillions of shrimps snapping their single oversized claw all at once. Snapping shrimps, members of the various Alpheus and Synalpheus species, are found in shallow tropical and subtrpoical waters. But it's even more interesting than it sounds. Video shot at 40,000 frames per second shows clearly that the noise occurs 700 microseconds after the claw has snapped shut. The noise comes from burst bubbles - not the shutting of the claw itself - an effect known as "cavitation". It works like this. A small bump on one side of the claw fits neatly into a groove on the other side. The claw is shut so rapidly that a jet of water travelling at 100 kilometres (62 miles) per hour squirts out, fast enough to create expanding bubbles of water vapour. When the water slows down and normal pressure is restored the bubbles collapse creating intense heat (as high as 20,000 degrees C), a loud pop and light - this last being a very rare phenomenon called sonoluminescence, where sound generates light. Shrimps use this nosie to stun prey, communicate and find mates. As well as ruining sonar, the sharp, hot intense noise makes dents in ships' propellors.
Isn't that just so cool? Science rules! I might share some more extracts in the future, cos it really is brilliant.
And now, The Great Gatsby, by F. Scott Fitzgerald. Yes, I know, I know, how can I not have read this before? I think I must be just about the only person in the world who didn't do this book at school, but nevermind. It's read now. And it was very good. Cynical, but sweet, wordy and wistful. It was somehow very joyful and very sad at the same time. It vividly conjured up a world that's gone and the twist at the end was a big surprise. A very well written book.
And finally, All the Pretty Horses, by Cormac McCarthy. Another great book. It's about two boys who saddle their horses and ride South into Mexico and have lots of misadventures. I found it a bit of a contradiction, because it's seemingly very rough and ready, and yet also very sophisticated. The simplicity and sparsity of the dialogue contrasts highly with the wordiness and fluidity of the narration. It's earthy and polished at the same time. I loved it, but I will admit it took me a while to get through it. It's not a light read. There is quite a bit of violence in it. It's also largely not in English. A fair amount of it is in Spanish, so a working knowledge of the language is beneficial to the reader!
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