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 …

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 …

A real reason, both religious and ethical, does not exist, but we can say that faith is carried on the ring finger left hand only for a social “custom”. The exchange of faiths that is between spouses during the wedding ceremony has very ancient origins and comes directly from the Germanic territories, after consolidating in those of the Roman Empire. Only in the Late Middle Ages was officially introduced into the wedding ceremony, with the emergence of a particular liturgy. The custom of putting the ring (both engagement and marriage) …

All bodies (the car, the human body and so on.) Have a tendency to lose or to accumulate electric charges through friction or even for a trivial contact (for example, the car is traveling “rubbed” by the wind). When you touch the car, the electricity accumulated on the body passes through the body of the passenger (and the car is “discharged”), from there the electrical shock. This phenomenon is called triboelettricità – electricity through friction – and there is more in dry days. In fact in those days conductivity (the …