Why :D 1: Why is light white?
Is it really white?
The light from the Sun looks white. But it is really made up of all the colors of the rainbow.
A prism is a specially shaped crystal. When white light shines through a prism, the light is separated into all its colors.
The light from the Sun looks white. But it is really made up of all the colors of the rainbow.
If you visited The land of the magic windows learned that the light you see is just one tiny bit of all the kinds of light energy beaming around the Universe--and around you!
Like energy passing through the ocean, light energy travels in waves, too. Some light travels in short, "choppy" waves. Other light travels in long, lazy waves. Blue light waves are shorter than red light waves.
All light travels in a straight line unless something gets in the way to—
- reflect it (like a mirror)
- bend it (like a prism)
- or scatter it (like molecules of the gases in the atmosphere)
Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
Closer to the horizon, the sky fades to a lighter blue or white. The sunlight reaching us from low in the sky has passed through even more air than the sunlight reaching us from overhead. As the sunlight has passed through all this air, the air molecules have scattered and rescattered the blue light many times in many directions. Also, the surface of Earth has reflected and scattered the light. All this scattering mixes the colors together again so we see more white and less blue.
What Makes a Red Sunset?
As the Sun gets lower in the sky, its light is passing through more of the atmosphere to reach you. Even more of the blue light is scattered, allowing the reds and yellows to pass straight through to your eyes.
Sometimes the whole western sky seems to glow. The sky appears red because larger particles of dust, pollution, and water vapor in the atmosphere reflect and scatter more of the reds and yellows.
Why does scattering matter?
How much of the Sun's light gets bounced around in Earth's atmosphere and how much gets reflected back into space? How much light gets soaked up by land and water, asphalt freeways and sunburned surfers? How much light do water and clouds reflect back into space? And why do we care?
Sunlight carries the energy that heats Earth and powers all life on Earth. Our climate is affected by how sunlight is scattered by forests, deserts, snow- and ice-covered surfaces, different types of clouds, smoke from forest fires, and other pollutants in the air.
MISR (for Multi-angle Imaging SpectroRadiometer) is one of five instruments onboard the Terra satellite. MISR has nine separate cameras that take pictures of Earth's atmosphere and surface from different angles as the Terra satellite passes over a region during its orbit.
MISR flies over a brush fire burning in Northern California.
Why 2 :D: Why do we snore?
Vibrations of soft tissues located at the back of our throats cause the noisy, annoying sounds of snoring that sometimes prevent non-snorers from getting their ZZZZs.
The palate, uvula and tonsils are the tissue structures that flap against each other when someone has too much tissue at the back of their mouth or when an obstruction is blocking the air passageway to the back of the throat.
People with snoring problems tend to have one of the following conditions:
- Poor muscle tone in the tongue and throat
- Excessive bulkiness of throat tissue
- Long soft palate and/or uvula tissue in the back of the mouth
- Obstructed nasal airways
Snoring can be a serious medical problem because it disturbs sleeping patterns and deprives the snorer of necessary rest.
Did you know?
Did you know?
- 20% of the population experiences snoring problems.
- Males and obese people have more problems with snoring.
- Snoring tends to be louder when a person sleeps on their back.
Why 3 :D: Why do we blink?
To oil, lube, and filter the eyes.
Blinking, as opposed to batting, our eyes automatically supplies two forms of moisture to our eyes, to keep them from drying out, and to keep foreign matter from entering and irritating our eyes. Eyelids themselves, our built-in "wind-shield wipers," are merely folds of skin, controlled by muscles capable of expanding and contracting so rapidly, that blinking does not impair our vision. Mother Nature lined the rims of our eyelids with 20-30 sebaceous, oil-producing glands, which are located between our eyelashes, and are invisible to the naked eye. Blinking automatically coats the eyelid and eyelashes with the lubricant it secretes, to prevent them from drying out.
Blinking also protects the eye from dryness by irrigating, not by irritating, the eye, The eyelid, through suction, automatically draws the fluid we cry with from the well we refer to as the tear duct over the eyeball, to irrigate, and to moisturize the eye. The process is similar to the manner in which the farmer uses water to irrigate his crops during a dry spell.
Yet another benefit of blinking, is to shield the eye from foreign bodies. Our eyelashes, short, curved, hairs, attached to the eyelids, serve as dust-catchers, as the blinking reflex causes them automatically to lower, when exposed to harsh elements. Nature endowed the camel with extraordinarily long, curly, eyelashes, to protect his eyes from sudden sandstorms in the desert. Incidentally, the "camel eyelash" look is one many women attempt to duplicate by using an eyelash curler! Eyebrows, by the way, also serve their purpose, as they catch the run-off perspiration produces.
Blinking also protects the eye from dryness by irrigating, not by irritating, the eye, The eyelid, through suction, automatically draws the fluid we cry with from the well we refer to as the tear duct over the eyeball, to irrigate, and to moisturize the eye. The process is similar to the manner in which the farmer uses water to irrigate his crops during a dry spell.
Yet another benefit of blinking, is to shield the eye from foreign bodies. Our eyelashes, short, curved, hairs, attached to the eyelids, serve as dust-catchers, as the blinking reflex causes them automatically to lower, when exposed to harsh elements. Nature endowed the camel with extraordinarily long, curly, eyelashes, to protect his eyes from sudden sandstorms in the desert. Incidentally, the "camel eyelash" look is one many women attempt to duplicate by using an eyelash curler! Eyebrows, by the way, also serve their purpose, as they catch the run-off perspiration produces.
Why 4 :D: Why do mosquito bites itch
Only the female mosquito feeds on blood. Though we commonly call them mosquito bites, she's not really biting you at all. The mosquito pierces the upper layer of your skin with her proboscis, a straw-like mouthpart that allows her to drink fluids. Once the proboscis breaks through the epidermis, the mosquito uses it to search for a blood vessel in the dermal layer underneath.
When she locates a vessel, the mosquito releases some of her saliva into the wound. Mosquito saliva contains an anti-coagulant that keeps your blood flowing until she is finished with her meal.
Now your immune system realizes something is going on, and histamine is produced to combat the foreign substance. The histamine reaches the area under attack, causing blood vessels there to swell. It's the action of the histamine that causes the red bump, called a wheal.
But what about the itching? When the blood vessels expand, nerves in the area become
Personal Reflection: Mosquito bites actually do not cause the itch but rather it is our own body that causes the itch when the blood vessels sweel and thus it causes the itch. I realised that to stop mosquito bites from itching you could
Personal Reflection: Mosquito bites actually do not cause the itch but rather it is our own body that causes the itch when the blood vessels sweel and thus it causes the itch. I realised that to stop mosquito bites from itching you could
- Make a paste of baking soda (bicarbonate of soda) mixed with warm water. One tablespoon to one pint of water is a good ratio to use.
- Gently apply to the affected area. Use your clean fingers, or a cotton swab, or a popsicle stick to apply.
- Leave on for a few minutes, then wash off with warm water
Why 5 :D: Why does Hair Turn Grey?
If you look at photos of President Obama taken before he ran for president and then more recently, you’ll notice a distinct difference: where there used to be only dark brown hair, there are now areas of gray dotting the landscape. It seems that the stress of running a country would turn any person’s hair gray. But is stress really to blame? And why does hair turn gray, even for those of us who don’t have jobs quite as stressful as President Obama’s?
Stress doesn’t actually turn hair gray—the color can't change once produced by hair follicles, so hair cannot suddenly turn gray if you are under a great deal of stress. If a single strand of hair starts out brown (or red or black or blond), it's never going to turn gray. Your hair follicles produce less color as they age, so when hair goes through its natural cycle of dying and being regenerated, it’s more likely to grow in as gray beginning after age 35. Genetics can play a role in when this starts. President Obama is in his mid-40s, so aging could explain his graying. But stress may have played a role, too.
Stress can trigger a common condition called telogen effluvium, which causes hair to shed at about three times the rate it normally does. The hair grows back, so the condition doesn’t cause balding. But if you’re middle-aged and your hair is falling out and regenerating more quickly because of stress, it’s possible that the hair that grows in will be gray instead of its original color.
Personal Reflection: After conducting research, I found out that hair turning grey might not be solely due to stress contrary to popular believe and yet it is more of times due to the genes. (PS. I had found a white hair on my head!)
Personal Reflection: After conducting research, I found out that hair turning grey might not be solely due to stress contrary to popular believe and yet it is more of times due to the genes. (PS. I had found a white hair on my head!)
Why 6 :D: Why is yawning contagious.. or is it?
For more than a minute, the star of the YouTube video called “I can make you yawn” stands in front of the camera yawning. And according to the comments posted below the video, it (mostly) lives up to the promise in the title. Why is it that watching someone else yawn—whether on your computer or in person—makes you yawn?
No one’s really sure why yawning is contagious. One theory is based on the assumption that yawning is a form of nonverbal communication. In baboons, extensive yawning among members of a group signals the time to sleep, typically with the leader (the “alpha male”) ending the ritual with a giant yawn. If our ancestors used yawning to communicate like baboons do, then the contagiousness of yawning may be an involuntary, genetically programmed phenomenon; once one person in the “tribe” yawns, others do so because this behavior pattern helped our evolutionary ancestors to communicate with one another.
Even more basic than the question of why yawning is contagious is the question of why anyone yawns in the first place. And we all do it about 10 times per hour, more often in the early morning and late evening. In fact, yawning starts before birth—a fetus in the womb yawns beginning as early as 11 weeks of development.
As common as it is, little is known for sure about yawning. Yawning probably doesn’t always indicate a need for sleep, and it doesn’t seem to have anything to do with the body having too little oxygen or too much carbon dioxide (which theoretically could be fixed by taking a big, deep yawn). This latter theory lost favor after a study in 1987 showed that volunteers subjected to high oxygen levels did not yawn less, and those exposed to high carbon dioxide did not yawn more.
Here are some of the most reasonable theories about why we yawn, though none has been proven:
- Yawning stretches out the lungs and nearby tissues, preventing tiny airways in the lungs from collapsing. This could explain why we seem to yawn at times when our breathing is shallow (when we’re tired, bored or just arising from bed).
- Yawning distributes a chemical called surfactant, a gooey liquid that coats the tiny air pockets in the lungs and helps to keep them open. Surfactant is critical to the ability of a newborn to survive outside the womb. This theory could explain why fetuses yawn during development as they prepare to use their lungs.
- Yawning stretches the muscles and joints, and increases the heart rate. For this reason, it may prepare the body for an increased level of alertness, especially after relaxation. This could explain why athletes and professional musicians often find themselves yawning just before periods of increased focus or activity.
Personal Reflection: Through this question, I feel that yawning might not be actually such a bad thing yet excessive yawning might not be good as well as it might indicate certain diseases and illnesses. Teachers shouldn't really scold us for yawning in their classes now!
Why 7 :D: Why do we need blood?
The liquid that runs through the body’s 95,000 km (60,000 miles) of blood vessels is an aver-moving supply train carrying a vast and relentless force of workers who labor nonstop. A single drop of blood holds more than 250 million separate cells, each with a job to do. Blood makes up about 7 percent of an average adult’s body weight , a volume of between 3.5 and 5 liters (6 and 81/2 UK pints; 71/2 and 101/2 US pints) – a mighty workforce indeed, which is being replenished at a rate of three million new cells every second.
We need blood to nourish our bodies with proteins, glucose, salts and vitamins. Most of these are carried in plasma, which constitutes about 55 percent of blood. Plasma, a straw-colourd fluid, is 95 percent water, with about as much salt as there is in seawater. That is why blood tastes salty. Also, plasma contains varying oils the works, ensuring that in healthy body the blood flows freely.
Most of blood’s other 45 percent is made up of red blood cells, which out-number the third constituent, white cells, by about 700 to 1. Red cells, or erythrocytes, are composed mainly of haemoglobin, a protein found in all animals, from insects and worms, to birds, fish and mammals. Their redness depends on how much oxygen this iron-charged pigment carries.
An average blood cell holds some 350 million haemoglobin molecules, which are made from haem and globin in the bone marrow. The red army’s job is to gather oxygen, which it does with great efficiency; each haemoglobin molecule can carry four molecules of oxygen. Body tissues need oxygen when their cells burn glucose and other fuels to make energy.
Carbon dioxide is a by-product of this reaction. After delivering their oxygen, the haemoglobin molecules don’t cruise back empty. The now not-so-red molecules transport carbon dioxide to the lungs, which expel it. All this hard labour finally wears out the red cells, which in a four-month life complete some 300,000 circuits of the body’s transport system.
Their workforce comrades, the white cells, are in effect the body’s defence force. And, like any efficient army, the are grouped into units. Once destroys enemy invaders, such as harmful bacteria. Another group acts as scavengers, quietly removing dead cells. Other units pronounce on poisons, nullifying their venom. The white cells are born in many places – in the bone marrow, the lymph nodes, the thymus and the spleen. If you have ever wondered why we have tonsils, white blood cells are a good reason. Some of them come from there.
In 1952, haematologist Jean Dausset discovered the substance in white blood cells that fights infection. Known as human leukocyte antigen (HLA), its components of our blood – the red and white corpuscles, the enzymes and platelets – show similar variations. The range is so vast that, apart from identical twins, no two human beings have the same blood patterns.
At high altitudes, the air is cleaner. People breathing it don’t need blood organisms that protect against diseases prevalent at sea level. That is why, when some people move from mountains to the coast, they may suddenly become ill. A famous example is of Bolivian Indians who in the 1930′s left their high plateaux homelands to fight in lowland jungles of the Gran Chaco. Though impressive in physique, most of them soon sickened and died.
Personal Reflection: Since blood is an important component of the human body, I forsee there will be great need for research in making artificial blood or grow them by stem cell etc. More articles on this http://www.scientificamerican.com/article.cfm?id=how-do-scientists-make-ar
Why :D 8: Why are some people color blind?
We recognize color because we have special receptors behind the retina at the back of the eye. Light enters the lens, passes through the whole of the retina, and strikes these receptors, which are divided into rods and cones.
Color perception depend mainly on the cones, which are of three kinds, each containing different color-sensitive pigments. One responds best to red (long wavelength) light, another to green (intermediate) and the rest to blue (short). These correspond to the primary colors in an artist’s paintbox. All the colors we see – between 120 and 150 hues – result from the combined stimulation of these cones, a mixing of the primary colors in the eye’s palette.
The lack of one kind of cone brings a failure to see a particular colour. Total color blindness, in which everything appears in shades of grey, is extremely rare. What we call colour blindness is usually an inability to distinguished from green. It can be caused by injury to the optic nerve and retina, but most people inherit it. It affects about 8 percent of white European males and less than 1 percent of females; it is less prevalent among Asians and even rarer among blacks. Women who are not themselves colour-blind may pass the defect to some of their children.
In a severe case, somebody with green blindness has difficulty distinguishing oranges, greens, brown and pale reds. Those with a red deficiency never see brilliant reds; all reds are duller.
Color blindness is usually detected by test with colored plates viewed in natural daylight. In the top plate, people with normal vision see a figure 8; those with red-green defect see 3, the totally color-blind cannot see a numeral. In the middle plate, the normal see 16; those with color defects see no numeral or a wrong one. In the bottom plate, the color-blind see a line windings its way from one x to the other
Personal Reflection: I checked with my dad about driving, and found out that drivers are not tested for color blindness. This could be a danger as they may not recognize the traffic signals. One of his friends told me they recognized by the intensity of light and position of signals since they cannot see the colors correctly.
Perhaps LTA should check for eyesight for color blindness.
This is also important for pilots etc, because they navigate by colors in the air or sea at night in visual signals
