Revealed: The secrets of belly button fluff
After three years of research, Georg Steinhauser, a chemist, has discovered a type of body hair that traps stray pieces of lint and draws them into the navel.
Dr Steinhauser made his discovery after studying 503 pieces of fluff from his own belly button.
When our eyes see colours, they are actually detecting the different wavelengths of the light hitting the retina. Colours are distinguished by their wavelengths, and the brain processes this information and produces a visual display that we experience as colour.
This means that colours only really exist within the brain – light is indeed travelling from objects to our eyes, and each object may well be transmitting/reflecting a different set of wavelengths of light; but what essentially defines a ‘colour’ as opposed to a ‘wavelength’ is created within the brain.
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Magenta is an “extraspectral” color. Sir Isaac Newton noticed that magenta did not exist in the spectrum of colors from white light when he played with prisms. But when he superimposed the red end of the spectrum on to the blue end, he saw the color magenta
Under the broad heading of What causes hangovers? which is addressed in the link, along with some other alcohol-related information.
Congeners are toxic chemicals that are formed during fermentation, some liquors have more of them than others. These congeners are widely responsible for headaches.
Word to the wise: if you can’t pronounce “congener” anymore, stop drinking.
(h/t to YT and John)
(remember: Beer is good)
Getting soldiers acclimated to stress, and weeding out those who can’t handle the truth it.
During mock interrogations, the prisoners’ heart rates skyrocket to more than 170 beats per minute for more than half an hour, even though they aren’t engaging in any physical activity. Meanwhile, their bodies pump more stress hormones than the amounts actually measured in aviators landing on aircraft carriers, troops awaiting ambushes in Vietnam, skydivers taking the plunge or patients awaiting major surgery. The levels of stress hormones are sufficient to turn off the immune system and to produce a catabolic state, in which the body begins to break down and feed on itself. The average weight loss in three days is 22 pounds.
My recent post on Haidinger’s brush reminded me of another optical phenomenon I have observed, and one that is a bit easier to see: the Pulfrich effect.
The Pulfrich effect is a phenomenon that gives the illusion of depth based on the response time of different light levels in the eye and how the brain interprets the delay. Lower light levels take longer to process, so if the image viewed by one eye is dimmer than the other, the signal from the dimmer view will lag in reaching your brain to be interpreted. With one eye darkened, something moving across your field of view will appear to get closer or further way.
When I first read about this, I consulted Wikipedia, which tells me
In the classic Pulfrich effect experiment a subject views a pendulum swinging in a plane perpendicular to the observer’s line of sight. When a neutral density filter (a darkened lens – typically gray) is placed in front of, say, the right eye the pendulum seems to take on an elliptical orbit, appearing closer as it swings toward the right and farther as it swings toward the left.
Well, gee, I work in an atomic physics lab. I can make a pendulum and have neutral density filters, so I went ahead an made up the experiment, using some scrap wire and a few optical-mount bases for the pendulum. And sure enough, with the right combination of filters (I think I ended up with ND=0.3 or 0.4) I was able to easily see the effect — the pendulum’s oscillation got closer at one end and further away at the other, and it reversed itself when I switched and darkened the other eye.
I wanted to show this off, so to make things a little easier I salvaged a damaged pair of sunglasses and popped one of the lenses shades out. (Not really lenses are they? OK, pedantic man says they are, albeit with an infinite focal length) That covers the eye better than the ND filter, which only has a 1″ diameter. I can use either the free eyepiece or the glasses. The biggest problem is getting people to look with both eyes — their natural tendency is to shut one eye and only look through the shade.
Weightless Workouts on the ISS
I was recently learning and reading about Haidinger’s Brush
Unlike some other types of animals, humans generally don’t perceive polarization of light, or rather we do so very weakly so it’s not something we normally notice. The link explains how to check for it and what to look for.
The eyes of men (AND women) are not designed to distinguish between different types of polarization, contrary to insects, cephalopods, many amphibians, fish, and other animals, for which nature possesses a different class of “colors” (but even common colors do not mean the same to everyone). However, a small quirk in the structure of the human eye gives us (by accident) the ability to tell apart different states of polarization. Thanks to this small aberration or “defect” of the eye we are not completely polarization-blind.
Yes !!! With some effort you can learn to see what remains invisible to most people! Without the help of any instrument you will be able to tell not only if the light you look at is strongly polarized or not, but also if it is linearly polarized or circularly polarized and, moreover, in which direction it vibrates or rotates. Any time that you raise your eyes to the blue sky you will be rewarded by the same clues that guide bees in their flight. Acquire P-Ray Vision !
I tried it with my LCD monitor (which, as we know, is polarized) with both a white and blue background, the latter for contrast to show the yellow. I think I see the yellow brush, but it’s not very distinct. I’ll keep trying, but I don’t think this is like those 3-D drawings that jump out at you all of the sudden.
Here’s another link explaining the phenomenon.
Study: Exercise Won’t Cure Obesity
Researchers from Loyola University Health System and other centers compared African American women in metropolitan Chicago with women in rural Nigeria. On average, the Chicago women weighed 184 pounds and the Nigerian women weighed 127 pounds.
Researchers had expected to find that the slimmer Nigerian women would be more physically active. To their surprise, they found no significant difference between the two groups in the amount of calories burned during physical activity.
“Decreased physical activity may not be the primary driver of the obesity epidemic,” said Loyola nutritionist Amy Luke, a member of the study team.
While it may be true that diet, not exercise, causes the obesity, it’s fallacious to conclude that exercise won’t make any difference. It just isn’t a factor in this example. You have two variables that affect weight (Calories in and Calories burned), and only see that one is different here. At the very basic level, it’s conservation of energy.
People burn more calories when they exercise. Thing is, they compensate by eating more, said Richard Cooper, co-author of the study and chairman of the Department of Preventive Medicine and Epidemiology.
“We would love to say that physical activity has a positive effect on weight control, but that does not appear to be the case,” Cooper said.
It’s not clear if this was tested in the study — there’s no mention in the story — so one doesn’t know if it was a crappy experiment or it’s crappy reporting.
The science du jour is physics of weight loss, which is useful for this time of year when some of us tend to act as sanctuary for some extra mass (those poor, persecuted cookies and brethren, seeking asylum)
Here’s my own The Physics of Weight Loss
Matt has just posted on the topic over at Built on Facts:
54! Surely something that difficult would burn a lot more calories, you’d think. And it does. The immense effort you expend in climbing is mostly budgeted to different bodily processes. You have to move extra air in and out of your lungs. You have to circulate blood at a much higher rate. You have to process the complicated chemistry required to keep your muscles moving. All of these things take energy, and by the time the shoe meets the stair most of the energy has already been lost, eventually ending up mostly in the form of heat. Your body can’t afford to overheat and so you begin sweating to carry the excess heat energy away. All that energy had to come from somewhere, and it came from the food you ate. By the time you’re on the observation deck looking over Manhattan you’ll have used up a lot more than 54 calories.
As Matt notes in his posts, this is all about thermodynamics. Your body is basically a heat engine operating somewhere around 25% efficiency, so that 54-Calorie change in potential energy is going to require that you burn about 200 Calories of food.
(related: No Sweat)
Getting punched in the face, in slow motion
Cheeky wave propagation. Wait for it …