One of the best blogs on science which will tell you about many amazing scientific facts:
Why Men Get Erection:
- When the signals from the brain and the spinal cord reach the nerve ends in the penis and the genital zone, the chemical compound nitric oxide (NO) is released.
- Nitric oxide then spreads through the genital area and especially the penis. Nitric oxide then triggers the following reactions.
- Blood vessels leading blood to the erectile bodies relax. Then more blood flows into the penis.
- Blood vessels leading from the erectile bodies constrict, making it difficult for blood to leave the bodies.
- The smooth muscles around the vessels in the erectile bodies relax, allowing these vessels to widen.
- The blood going into the erectile bodies will then fill up in the vessels of the bodies and inflate the bodies to a much larger volume.
- The inflated bodies will get straight and hard. The growing erectile bodies will inflate the whole penis and make the penis rise.
- Since the erectile bodies continues backwards between the man’s legs, also this area swells and fixes the penis rigidly so that it does not sway from side to side when fully erected.
Why do We Yawn:
No one knows why we yawn. There are lots of theories, some talk about it signalling tiredness or getting oxygen to the brain, others mention clearing out stale air from the lungs and reducing blood carbon dioxide levels. Most are baloney. But, one thing that is certain, yawns can be infectious. Catch sight of someone yawning, and nine times out of ten, you will yawn yourself within a few seconds. But, that still doesn’t really answer the question, why do we yawn? Is such an infectious yawn a message to others in the group that it’s time for bed? Probably not, otherwise why yawn first thing on getting out of bed? Either way researchers have found that people with autism spectrum disorder don’t tend to succumb to an infectious yawn.
Why do We Dream:
Consistent with the psychoanalytic perspective, Sigmund Freud’s theory of dreams suggested that dreams were a representation of unconscious desires, thoughts and motivations. According to Freud’s psychoanalytic view of personality, people are driven by aggressive and sexual instincts that are repressed from conscious awareness. While these thoughts are not consciously expressed, Freud suggested that they find their way into our awareness via dreams.
In his famous book The Interpretation of Dreams, Freud wrote that dreams are "...disguised fulfillments of repressed wishes."1 He also described two different components of dreams: manifest content and latent content. Manifest content is the actual images, thoughts and content contained within the dream, while the latent content is the hidden psychological meaning of the dream.
Freud’s theory contributed to the popularity of dream interpretation, which remains popular today. However, research has failed to demonstrate that the manifest content disguises the real psychological significance of a dream.
Why do Stars Fall:
A "falling star" or a "shooting star" has nothing at all to do with a star! These amazing streaks of light you can sometimes see in the night sky are caused by tiny bits of dust and rock called meteoroids falling into the Earth's atmosphere and burning up. The short-lived trail of light the burning meteoroid produces is called a meteor. Meteors are commonly called falling stars or shooting stars. If any part of the meteoroid survives burning up and actually hits the Earth, that remaining bit is then called a meteorite.
At certain times of year, you are likely to see a great number of meteors in the night sky. These events are called meteor showers and they occur when the Earth passes through the trail of debris left by a comet as it orbits the Sun. These showers are given names based on the constellation present in the sky from which they appear to originate. For example, the Leonid Meteor Shower, or Leonids, appear to originate in the constellation Leo. It is important to understand that the meteoroids (and therefore the meteors) do not really originate from the constellations or any of the stars in the constellations, however. They just seem to come from that part of the sky because of the way the Earth encounters the particles moving in the path of the comet's orbit. Associating the shower name with the region of the sky they seem to come from just helps astronomers know where to look!
Why is Earth Round:
To a first-order approximation the Earth is round. This
is due to gravity. Gravity pulls with equal strength in all
directions; therefore any variations from a spherical
shape will lead to gravitational forces that
bring the shape back into that of a sphere.
This is without considering the rotation of the earth,
however. The rotation of the earth adds centrifugal
effects, which cause the earth to bulge slightly at
its equator and flatten slightly at its poles.
(This is like twirling a rock on the end of a string
and then letting go--the rock flies away from the
twirler.) Because of these centrifugal effects, the
distance from the center of the earth to the surface
of the earth is about 0.33% shorter at the poles
compared to the equator.
Why is Sun Yellow:
Sun is made up of gases mainly like hydrogen, helium and small amount of other elements like sulphur, magnesium, carbon, neon, iron, oxygen, nickel, chromium and calcium. Temperature on the surface of sun is approximately 5780K giving the sun white color but it often appears yellow to us when we look at the sun from the earth because of the atmospheric scattering of light.
When white light coming from the sun towards the earth passes through the atmosphere of the earth it scatters the blue light (which is responsible for the sky to appear blue) and is left with red color light which appears to us as yellow. When sun goes down in the west during sunset more blue light is scattered than normal so sun appears to us more dark say orange or red. So it can be said that when we look the sun from the earth it appears yellowish but if we move to the space, out of the atmosphere than we will surely notice a slight change in the color of sun and its brightness too.
Some people believe that the appearance of sun is only the interpretation of human eye that the light comes from the sun and strikes our retina visual cortex then starts processing and finally tells brain that the light is yellow in color.
Color is detected by photosensitive cells in our eyes which are known as cones and some animals do not have these cones. So it can be possible that they see this light as somewhat grey but this is not actually proved and we are not sure about it. They have black-white rods in their retina which have the high light sensitivity.
Why do We Die:
Death is the termination of the biological functions that define a living organism. It refers both to a particular event and to the condition that results thereby. The true nature of the latter has, for millennia, been a central concern of the world's religious traditions and of philosophical enquiry. Belief in some kind of afterlife or rebirth is a central aspect of many religious traditions.
Humans and the vast majority of other animals die in due course from senescence. Remarkable exceptions include the hydra, and the jellyfish turritopsis nutricula, which is thought to possess in effect biological immortality.
Intervening phenomena which commonly bring about death earlier include malnutrition, disease, or accidents resulting in terminal physical injury. Predation is a cause of death for many species. Intentional human activity causing death includes suicide, homicide, and war. Roughly 150,000 people die each day across the globe. Death in the natural world can also occur as an indirect result of human activity: an increasing cause of species depletion in recent times has been destruction of ecosystems as a consequence of the widening spread of industrial technology.
Physiological death is now seen as less an event than a process: conditions once considered indicative of death are now reversible. Where in the process a dividing line is drawn between life and death depends on factors beyond the presence or absence of vital signs. In general, clinical death is neither necessary nor sufficient for a determination of legal death. A patient with working heart and lungs determined to be brain dead can be pronounced legally dead without clinical death occurring. Precise medical definition of death, in other words, becomes more problematic, paradoxically, as scientific knowledge and technology advance.
source of whole data: wikipedia.org, ezinearticles.com, msnbc.com, sciencebase.com, starchild.com and encyclopedia
