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U know why the fireflies glow?

admin — Tue, 10 Mar 2009 13:04:01 +0000

The firefly is an insect which is particularly known for its characteristic luminescence. This animal has special abdominal organs, which cause a chemical reaction with the organic synthesis of an enzyme called luciferasi.

The light produced is useful because from these insects it can be exploited as a mean of communication between individuals of the same species, probably as a sexual recall as well, that could draw the prey too. It is curious to note that the adult insect issues, generally, intermittent light, while the larvae shine light sets.

U know why ‘ostriches’ hide their heads in the sand ?

admin — Sat, 22 Nov 2008 13:10:14 +0000

The reason for this behavior on the part of ostriches is ignored by everyone, why? Simple … because it’s false! Indeed, the popular belief that ostriches put their heads in the sand in case of danger, is wrong and has never been recorded.

However, when there is no other possibility of escape evident, a bird can lie down on the ground with head and neck stretched forward and remain firm in the hope that it is ignored by his enemy. This strategy has similarly taken by a bird in hatching when feel that the danger is nearby.

But it is plausible that this belief is born from a visual interpretation wrong: in fact, when an ostrich lowers his head between the foliage to eat, it seems, for an optical effect, like he has its head hidden between the sand.

U know why ‘the sky’ is blue?

admin — Tue, 18 Nov 2008 18:50:40 +0000

The visible white light coming from the Sun is composed from superposition of electromagnetic waves of different wavelengths ranging from the radiation that we perceive as violet, to the radiation that we recieve as red then blue, green, yellow, orange. The dust particles and droplets of water present in the atmosphere are much larger than the wavelength of visible light: in this case the light is reflected in all directions equally, regardless of its wavelength. The gas molecules are smaller and the light behaves differently depending on its wavelength. The red light has a wavelength greater and tends to “bypass” the smaller particles without “seeing” this light, therefore, very weakly interacting with the atmosphere and its spread continuing straight along the original direction. In contrast, the blue light has a wavelength less “aware” of the presence of molecules that is reflected in all directions. Then, crossing the atmosphere, most of the majority wavelength radiation continues its trajectory straight ahead. The red light, orange and yellow are affected only minimally by the presence of air. In contrast, the blue light is diffused in all directions. In whatever direction we look, part of this light reaches our eyes. The sky therefore appears blue.

U know why ‘the yawning’ is contagious?

admin — Tue, 18 Nov 2008 15:05:26 +0000

A portion of the brain that plays an important role in triggering the yawn is the hypothalamus (where are also guarded the centers that synchronize sleep and wakefulness, hunger and thirst, body temperature). In particular, some neurotransmitters (including dopamine) and neuropeptide have an important role in stimulating this behavior. Yawn is a stereotyped behaviour and there are not differences of sex, race, age in the way you yawn: there is a long inhalation followed by a brief exhalation during which it is very difficult, almost impossible, to avoid opening your mouth and get some ‘air. Throughout the average yawn lasts six seconds. It is the empathy that makes us not resist a yawn when we see someone do it in front of us and the phenomenon affects up to 60% of people. The psychologist Steven Platek of Drexel University in Philadelphia in Pennsylvania said that it is a behaviour done in unconscious way, and imitating them is the result of the ability to identify in the mental state of another person. Platek investigated the phenomenon yawn recruiting a group of people and making them look a series of videos that people sent in the yawn or simply during conversations on the subject yawn. Within a short time from 40 to 60% of viewers do not stand up and begin to yawn themselves. According to the researchers who are immune to infection and not yawning as the others are just individuals with little ability to get in the shoes of others, individuals who lack the human characteristic of showing empathy for others. Ronald Baenninger, expert and author of research on yawning at Temple University in Philadelphia, commenting on the news, claims that the results are explained by evolutionary point of view. In fact, he says, the contagious yawning may have helped our ancestors to coordinate the periods of activity and rest. “It is important that all members of a group – says Baenninger-are ready to do the same thing contemporaneously.” Even with this research, however, emphasize the two experts, the causes of the phenomenon yawn are not yet fully clarified. For those who consider the yawn is the effect of lack of oxygen and, therefore, need to inhale more deeply, the denial came from studies that showed no significant difference between the frequency of yawning rooms in poor or rich in oxygen. Baenninger concludes that it is more likely to think yawn as a measure to face involuntary keep awake to the brain, not by chance yawn when fighting sleep at night when we must continue to engage, or in the morning when we win sleep and take action.