Why Don’t Penguins’ Feet Freeze?

Non-freezing penguin feet and other oddities explained – seems like a advertisment for the book (Why Don’t Penguins’ Feet Freeze?) more than a news article, but I went ahead a googled for the answers:

Q: Why don’t penguins’ feet freeze?
A: The system that stops a penguin’s foot from freezing is very elaborate and sophisticated and employs two mechanisms. The first one allows the penguin to control the rate of blood flowing to its feet by varying the diameter of arterial vessels supplying the blood. In cold conditions the flow is reduced, when it is warm the flow increases. The second mechanism takes the form of ‘counter current heat exchangers’ at the top of the legs. The arteries, which supply warm blood and oxygen to the penguin’s feet break up into many small vessels which are closely linked to similar numbers of venous vessels bringing cold blood back from the feet. So, when heat is lost from the arterial vessels, the venous vessels running in the opposite direction pick it up and carry it back through the body, rather than out through the feet. This means that in the very remote regions of the skin, cells get oxygen but heat isn’t lost through this skin. (from answerbank)

Q: Why hair turns grey?
A: As we get older, the pigment cells in our hair follicles gradually die. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color – like gray, silver, or white – as it grows. As people continue to get older, fewer pigment cells will be around to produce melanin. Eventually, the hair will look completely gray. (from KidsHealth)

Q: Why fingers get crinkled in the bath?
A: Your fingers and toes tend to wrinkle because of the kind of skin surrounding your hands and feet. As this site in our Skin category tells me, the tops of your fingers and the soles of your feet are covered by a thick, tough layer of skin called the stratum corneum. Notice how the skin of your eyelids is much softer and thinner than on your hands — that’s because it needs flexibility rather than strength. When the stratum corneum (which is Latin for “horny layer”) sits in a tub or a pool for a long time, it absorbs water. As the skin expands with water, it runs out of room to grow, and wrinkles up! (from Ask Earl)

Q: Is the Great Wall of China really visible from space?
A: “You can see the Great Wall,” Lu says. But it’s less visible than a lot of other objects. And you have to know where to look. (from SPACE.com)

Q: Why left-handers are at greater risk of accidents?
A: I wasn’t able to find much sources in regards to this, but I’m pretty sure it’s because since the majority of the human popluation (~90%) are right handed, machinaries, tools, and even most mice are customized for the right hand, making the job more dangerous when someone who is left handed attempts. I’m not sure if this is exactly the case, but to open a bottle or unscrew a bolt, you turn counter-clockwise. For right handers, that means pushing out the wrench with your right hand. For left handers, that means pulling in the wrench with your left hand, and you obviously should know if pushing out or pulling in has more power. I did find an interesting article, but it seems to no longer be “free”, but clippets of it are on this person’s blog: Are left-handed people nature’s way of starting a fight?

Q: How do ants manage to survive in the microwave?
A: One thing working in the ants’ favor is that they don’t have much liquid in their bodies, so the microwaves– which cook meats by heating their water content– would act more slowly on ants than on people. That could buy the poor ants some time to save themselves. But how? By seeking out the dead spots, naturally. Microwave ovens have them just like concert halls, creating those annoying cold pockets in cooked foods. The ants probably are quite uncomfortable when they are bathed in microwave radiation, so they try to get away. If they find a dead spot they feel better, so they stay there and survive. (from The HooK)

Despite what mothers may have said, there is no connection between being cold and having one.
Though there is no direct connection, isn’t putting your body into a lower temperature make you immune system weaker making it easier for virus to enter?

Q: Why is snot green?
A: Of all the body cavities in contact with the outside world, the nose is probably one of the most hospitable: it is warm, very well aerated, moist and supplies unlimited quantities of bacterial food secreted continuously by the nasal mucosa (mucus contains quantities of glycoprotein and dissolved salts). In other words it is an ideal breeding ground for bacteria, which are always present. Many of the common bacteria associated with humans are coloured, Staphylococcus aureus is a golden yellow, for example, and Pseudomonas pyocyanea (to give it its older, but more explicit name) is a shade of blue. Normally these and the multitude of other organisms that are inhaled continuously into the nose are flushed out by runny mucus, which is swallowed. The bacteria are usually digested. However, if a situation arises where the flow of mucus slows down and then becomes much thicker in response to an infection of any kind, then the bacteria, in their ideal home, can multiply and produce the coloured mucus described. This, as many parents know, is one of the less endearing characteristics of babies and young children! And, by the way, if you’re still wondering where the green colour comes from, remember what happens when you add blue to yellow. (from New Scientist – they actually took down this page and I had to find it through WayBackMachine. I think it has to do with the fact they’re releasing this book.)

Q: Does beheading hurt?
A: Yes, beheading hurts. How much depends on the executioner’s skill, or lack of it. When Mary, Queen of Scots, was executed at Fotheringay Castle in 1587, a clumsy headsman gave her three strokes without quite managing to sever her head. The headsman then had to saw though the skin and gristle with his sheath knife before the job could be regarded as complete. The profound, protracted groan Mary gave when the axe first hit left the horrified witnesses in no doubt that her pain was excruciating. (from New Scientist)

Q: Why is the sky blue?
A: The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air. However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue. As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white. (from Science Made Simple)

7 Replies to “Why Don’t Penguins’ Feet Freeze?”

  1. Interesting, though can you explain why only looking up turns blue and not straight or down? If I was in a very tall tower and looked straight for hundreds of miles and then put a white wall. Would that white wall have a bluish hint to it?

    According to Wikipedia, The colour of the sky is a result of diffuse sky radiation and the fact that air is actually a very transparent blue color.

    The source you provided has the same text the source of the Wikipedia entry. Honestly, it doesn’t look like much of a reputable source to me, but I can accept air has a hint of blue in it, but it doesn’t explain why only up is blue, but not straight or down.

    The pictures provided “as proof” can also be explained with scattering light. Scattering light just depends on the angle you’re looking at.

    If the sky is blue just because air is blue, then wouldn’t looking at Earth from space mean everything have a blueish tint?

    //krunk (^_^x)

  2. I’ve read a lot of the Bad Physics articles and haven’t spotted any glaring errors (more than I can say for Wikipedia), so I think it’s fairly reputable.

    Re: seeing earth from space: The earth has a pretty high albedo, whereas empty space has zero. Earth’s reflectivity is such that it obscures the very lightly tinted air when viewed from space. (Though you can still see the blue atmosphere at the edge of the planet in certain pictures from space, provided they’re close enough; compared to the width of the planet, the atmosphere is a very thin layer, after all.)

  3. Once again, it’s one word vs another. What proof exactly can he that it’s not scattering light or whatever the name of the theory is that everyone’s been saying all along?

    He gives simple analogies and examples and lets even say I believe him when he says air has a light blue hint, but I don’t recall seeing any proof that refutes the scattering light theory.

    Plus, there’s no reason for Earth to not have a blue hint if seen from space. If I put a ton of water between me and the object I want to see, the color is defintely affected. Saying because of Earth’s reflectivity cancels out the blueness just refutes that air is blue theory.

    //krunk (^_^x)

  4. To be clear, Rayleigh scattering actually says the same thing — i.e., that air is blue (“shorter wavelength light is absorbed by the gas molecules”). Beaty’s main point is that people focus on the complicated physics of it when the answer to the original question (“Why is the sky blue?”) is actually very simple.

    And the Earth probably does have a “blue hint” when viewed from space. But given the magnitude of its brightness relative to the tint, it’s practically undetectable.

    Imagine watching a film of something green shown via an old-fashioned movie projector. The celluloid film is acting like a filter, the way air does in Beaty’s model. Now, replace the projector’s bulb with something magnitudes of order brighter — the projection, even though it’s coming through the same filter, will appear white, or very nearly so.

  5. Like I said, I have no problems believing that the air is blue, but what is to say that the scattering light doesn’t contribute to the blueness? Who is to say that “most” of the blueness comes from the color of air or from scattering light?

    Just because air is blue, doesn’t mean most of the blue color is due to that reason.

    Just like how he explained water is brown, if I had mixed a brown powder in a pool of water, is that water brown because water is brown, or is it because I put the powder in?

    Many questions have multiple answers. Many effects have multiple contributors. Usually the one that contributes the most is given as the correct answer.

    My question now is how do you prove that because air is blue, that most of the blueness comes because of that? How do you prove that it’s not the scattering effect that is providing most of the blueness.

    The scattering effect on the other hand, explains a lot more than just blue. It explains why air can be red, orange, yellow, etc, when you look towards the horizon or during a sunset/sunrise. If I had a glass cube or sphere full of air in space, the entire object WILL NOT be blue. Why? Because you need a sorce of light in order to see the color, and with any source of light, the scattering effect will occur (if the scattering effect is real), creating different colors in the air.

    //krunk (^_^x)

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