Science & Mathematics - 2 September 2006

who invinted glasses? I know that Iben Sina (An Arab scientist started working on lenses but I need to know who wokred further on).

2006-09-02 09:25:18 · 12 answers · asked by Anonymous in Other - Science

2006-09-02 09:25:08 · 15 answers · asked by Andy S 6 in Other - Science

Why can't we see in the dark like other creatures of the dark do?

I know the reason lies in the special layer found in cats' eyes called tapetum lucidum which acts like mirror.

But, what led to the formation of this layer? Did it come as an adaptation to living in the dark?

Or, were they primarily "designed" to live and hunt in the dark?

If our cavemen ancestors weren't afraid of the dark and the hunting cats; and had they ventured in the dark more often.... Would it have helped us to gain a better "night vision"?

Why must we sleep at nights? I guess, in the earlier times it was because there was a danger of the big cats and wolves... Now what?

I hope you enjoy answering... please do!

(I had to "dumb down" the title of this question due to Answers' character limit. Extremely sorry for that.)

2006-09-02 09:23:35 · 12 answers · asked by Abhyudaya 6 in Zoology

There are items like night vision, back up mirrors one the back of trucks, tripac units.

2006-09-02 09:23:09 · 6 answers · asked by pebbleswallen 1 in Engineering

2006-09-02 09:21:44 · 4 answers · asked by winston m 1 in Chemistry

2006-09-02 09:19:02 · 4 answers · asked by AARON F 1 in Mathematics

is it

x < -3/4 ?

2006-09-02 09:12:53 · 12 answers · asked by chris 2 in Mathematics

i have a stepper motor with 4 wires . red , orange, yellow , brown,

The label on top says something like this

STH-55D007-03
1.8 Deg/step 36 ohms
No 21492
SHINANO KENSHI CO LTD JAPAN.

but I went through the shinano kenshi product web site but couldnt find the specs or the catalogue for this model STH - 55D007-03

Plz need some help

this is important... :)

regards

2006-09-02 09:09:24 · 5 answers · asked by CodeRed 3 in Engineering

Why isn't that the term for the scientists that study meteors?

2006-09-02 09:03:18 · 5 answers · asked by lrad1952 5 in Weather

and does it change if multiple people are being dealt hands from the same deck?

2006-09-02 09:00:49 · 9 answers · asked by perk 2 in Mathematics

I am nearsighted but corrected, have hardly any accommodation capability, and have been told I have incipient cataracts. The optometrist says my retinas are fine. Over the past couple of years I have noticed a strange phenomenon: my corrected vision is pretty good at night and at light levels comparable to the optometrist's eye chart, but in bright light it gets blurry. I don't think it's because of cataracts (I don't notice any fogging) but it could be due to an asphericity of the lens or of the eyeball surface, which could cause the average focal length to change as the iris opening changes between wide and narrow. So my question is, would a lens replacement (the recommended remedy for the cataracts) fix the focus problem, or is eyeball surface asphericity a possible cause? Do cataracts change the lens shape? Are there other possible causes given that the retinas are healthy?

2006-09-02 08:59:25 · 1 answers · asked by kirchwey 7 in Medicine

2006-09-02 08:58:08 · 5 answers · asked by ha h 1 in Other - Science

are all of the versions of ti-3 and 84 allowed?

2006-09-02 08:58:05 · 6 answers · asked by Icy 2 in Mathematics

i know that a woman is born with a pre determined amount but wonder averagely how many she will produce

2006-09-02 08:55:29 · 15 answers · asked by danchip 2 in Medicine

2006-09-02 08:50:11 · 3 answers · asked by Anonymous in Engineering

2006-09-02 08:47:56 · 43 answers · asked by kmc1169 2 in Mathematics

2006-09-02 08:43:34 · 2 answers · asked by crazyfrog 2 in Physics

this ones more complicated. my teacher says that you need to use all three symbols (conjunction, disjuncion, and not)

i swear if the answer to this one is as simple as the last one i posted im gonna kick myself

Use the symbols ^(conjunction), disjunction, and '(not) to form a sentence involving p and q whose truth table is given

p q ?
T T F
T F F
F T F
F F F

so make a sentence thatll make the truth table true

2006-09-02 08:38:56 · 4 answers · asked by krispy106 1 in Mathematics

2006-09-02 08:38:32 · 12 answers · asked by crazyfrog 2 in Earth Sciences & Geology

I was watching a movie last night, the main character was about to inject drug into arm. First he hit his arm a few times there, then pumped his arm a few times. I understand pumping the arm to increase the vein size, but why hit it?

2006-09-02 08:37:00 · 5 answers · asked by Joy_Brigade 3 in Medicine

2006-09-02 08:35:27 · 11 answers · asked by yukiphong2006 1 in Other - Science

2006-09-02 08:33:06 · 11 answers · asked by Thick Chick 2 in Mathematics

When a high-speed passenger train traveling at 161 km/h rounds a bend, the engineer is shocked to see that a locomotive has improperly entered onto the track from a siding and is a distance D= 676 m ahead. The locomotive is moving at 29.0 km/h. The engineer of the high-speed train immediately applies the brakes. What must be the magnitude of the resulting deceleration if a collision is to be just avoided?

2006-09-02 08:32:22 · 7 answers · asked by afchica101 1 in Physics

i need steps.

2006-09-02 08:30:51 · 12 answers · asked by Mallorie Z 1 in Mathematics

2006-09-02 08:29:39 · 3 answers · asked by Bobby 1 in Engineering

2006-09-02 08:29:14 · 4 answers · asked by jennyrosemathew 2 in Biology

2006-09-02 08:27:11 · 2 answers · asked by karla g 1 in Mathematics

my 4th question won't fit... 4)how many feet is 162 centimetres? so in total :
1) how many feet is 181 centimetres?
2)how many feet is 177 centimetres?
3)how many feet is 184 centimetres?
4)how many feet is 162 centimetres?

please answer by number example:

1)
2)
3)
4)
thanx

2006-09-02 08:24:23 · 5 answers · asked by humanitarian 2 in Mathematics

I need a down and dirty explanation of rotation periods applied to Astronomy. What properties and factors are involved in it, how exactly do they affect it and any available formulas to determine a rotation period. I need this to be kinda simple though, I just need a functional understanding of this so I can think of plausible solar systems for a game I'm designing.

2006-09-02 08:23:53 · 5 answers · asked by cactuar2k 3 in Astronomy & Space

As far as I know, they were both invented by man.

2006-09-02 08:23:24 · 6 answers · asked by Ejsenstejn 2 in Biology