I need a sketch of information regarding the topic. Please, please help me. I need it in a school project in Physics. I am a senior high school student. If you can help me, I would really appreciate it. Thanks!
2006-11-26 21:24:55 · 3 answers · asked by dimple106 1 in Science & Mathematics ➔ Physics
its cat's eye's, not dog's. when the light reflects on to a cat it glows, Cats' eyes
One night, a road-mender from Yorkshire was driving home and swerved to avoid a cat – which he noticed because its eyes had reflected his headlamps. If Percy Shaw hadn't seen that cat's eyes, he would have driven straight over a precipice. He went on to develop one of the simplest, but most effective, road safety devices: a road stud with 'retroreflectors' that send a beam of light back on a parallel path to the ray that enters, just as the retina of a real cat's eye works.
Shaw's glass studs were maintenance-free and even incorporated a self-cleaning method using rainwater, inspired by tear glands and eyelids. He patented the design in 1933, the first 50 were fitted to a road in Bradford and he went on to become a millionaire and OBE.
Most cats' eyes on British roads today are white and are positioned down the centre of a road; red cats' eyes mark out a motorway hard shoulder; amber denotes the central reservation; green are for a junction; and mark out blue for designated police sliproads.
Modern solar-powered LED road studs are now making their debut, but are more expensive to make and may not last so long.
2006-11-26 21:31:32 · answer #1 · answered by rachie 4 · 0⤊ 0⤋
Rachie has answered this question amazingly comprehensively and I can only add that the phenomenom is seen in the 'red eye' which often appears on photographs of humans taken with flash. Because such photos are usually taken indoors in darkish surroundings the subjects irises will be wide open and the flash reflects back, as previously described. Many modern cameras/flash guns attempt to overcome this problem by firing millisecond bursts of 'pre flash' which is designed to cause the irises to close
2006-11-26 21:41:12 · answer #2 · answered by rdenig_male 7 · 0⤊ 0⤋
http://dogs.about.com/cs/generalcare/a/tapetum.htm
http://images.google.co.uk/images?svnum=10&hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=tapetum+lucidum&spell=1
2006-11-26 21:35:03 · answer #3 · answered by Anonymous · 0⤊ 0⤋