References
Kapany, N. S. (2011). Fiber Optics. Encyclopedia Americana. Retrieved May 25, 2011, from Grolier Online http://ea.grolier.com/article?id=0155500-00
Lines, M. E. (2011). Fiber Optics. Grolier Multimedia Encyclopedia. Retrieved May 25, 2011, from Grolier Online http://gme.grolier.com/article?assetid=0105350-0
Maddox, N. (2011). What is Fiber Optic Cable used for. Retrieved May 25, 2011, from
Hecht, J. (2011). Fiber Optics. The New Book of Knowledge. Retrieved May 25, 2011, from Grolier Online
Is it possible for something to be invisible?
Imagine you could have an invisibility cloak like that of Harry Potter. What would it look like? It would have to possess the exact same index of refraction as that of its surrounding medium. If the index of refraction of the two mediums were the same, the light rays would pass through wihtout bending at all. Using Snell's law, we discover that if the index of refraction were identical, the angle of incident and the angle of refraction would be identical as well. The following picture shows a glass rod made from pyrex placed in a solution of Karo Corn Syrup and water. Because the index of refraction of the corn syrup is higher than that of the pyrex, water is added because water's index of refraction is much lower.
How does the eye see colours?
Our eyes contain red, blue, and green cone cells. This means that we only see red, blue, and green. When we see other colours, we are really seeing the combination of two (or three) other colours. For example, when we see yellow, we really see a combination of red and green. Orange would be a combination of green and red, with a higher concentration of red. Green and blue make cyan, and red and blue make magenta. White is a combination of all three, red, green, and blue. When we see any colour, the cone cells of that colour send signals to our brain. For example, when we see yellow, the red and green cone cells would send signals to our brain and we would know that what we see is yellow.
What causes colour blindness?
We know that seeing colour is a result of our red, green and blue cone cells sending signals to our brain. What happens when there is a problem with these cone cells? Colour blindness is the result of a defect in one or more types of cone cells. Colour blindness is a condition in which the eyes have difficulty distinguishing certain colours. Someone who has green colour blindness has a defect with their green cone cells (same with blue and red). Blue colour blindness and monochromatism (only able to see black, grey, and white) are very rare. Green colour blindness is called deutranopia, red colour blindness is called protanopia and blue coulour blindness is called tritanopia. Colour blindness is usually a genetic disorder but can also be caused by damage to the retina or the optic nerve (the nerve that takes information from the eye to the brain).
How does fiber optics work?
Fibre optics is the transmission of light through thin, transparent fibres. These fibres keep the light in by total internal reflection – a process that happens when the
incident ray of a light ray strikes the boundary of a medium at an angle that is larger than its critical angle. In a fibre, the core has a higher index of refraction than the material surrounding it and the light reflects from that material back to the core, allowing the light to travel down the fibre. These fibres are generally made of glass and are flexible. Fibre optic technology is very important in our world today. It is used for telecommunications and networking. In the medical field, fiber optic technology is used to capture images of internal organs. Fiber optic cables connect the entire world through the Internet.
Why can't humans hold their breath for a long time?
When we breathe, we inspire oxygen and we expire cardon dioxide. The oxygen and carbon dioxide are transferred in tiny blood vessels surrounding the alveoli. This prossess occurs through diffusion. However, as humans, we need to inhale and exhale very frequently. There are several reasons for this. These reasons include the fact that all our organs need oxygen to function. Another reason is because cardon dioxide has a higher level of acidity than oxygen (measured with the PH scale). When the acidic carbon dioxide remains in our bloodstream for too long, it reacts with the blood and sends signals to the brain to let out the carbon dioxide and replenish the oxygen.
How do breathalyzers work?
Breathalyzers are used to detect one's alocohol level. This is a very important process that officers use to keep drunk drivers off the road, to ensure the safety of roads. Breathalyzers are a very practical example of how we use physical reactions in our everyday lives. Breathalyzers contain sulfuric acid and other chemicals which react with alcohol. To test a driver's alcohol level, they are required to breathe into the sulfuric acid mixture. The sulfuric acid will then remove the alcohol from the air into a liquid solution. The breathalyzer will change colour, depending on the BAC (blood alcohol content, the ratio of alcohol to blood).
What is the difference between incomplete and complete combustion?
Combustion is a type of chemical reaction that usually involves oxygen. For combustion to occur, oxygen combines with another compound to form water and carbon dioxide. Combustion usually results in the production of light and heat in the form of a flame. There are two types of combustion: incomplete and complete combustion. Incomplete combustion is the type of combustion in which there is not enough oxygen or a high enough temperature for the carbon to turn into carbon dioxide. This can sometimes lead to the production of carbon monoxide, which is very harmful to the human body. Incomplete combustion will produce a yellow flame. An example of an incomplete combustion is burning paper because there are remnants of ash. Complete combustion is when the substance is completely burned and only carbon dioxide and water remain. many magicians use paper with extra oxygen molecules. This special paper will burn completely leaving no traces when burned. Complete combustion produces a more orange or blue flame.
How do organisms produce light without producing heat (luminescence)?
Living organisms produce light without producing heat through a chemical reaction resulting in bioluminescence. Bioluminescence is luminescence occuring in a living organism. Bioluminescence can be found infireflies, jellyfish, and many other ocean creatures. The light emitted by ocean creatures is usually a blue or green colour because blue light travels best in water. Light from marine creatures is made in specialised organs called photophores. Inside the photophores there are two chemicals that react with each other resluting in the emission of light. These two chemicals are luciferin and luciferase. The luciferin is the chemical that actually creates the light and the luciferase is the chemical that triggers this reaction. For many marine organisms, bioluminescence is their form of survival. It is used as a warning to predetors, as a camouflage, or as a lure for prey. Bioluminescence is a beautiful phomenon of our Earth that is yet to be fully discovered.
To learn more about bioluminescence, you can watch this video: http://www.ted.com/talks/edith_widder_the_weird_and_wonderful_world_of_bioluminescence.html
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