The book of wonders : $b gives plain and simple answers to the thousands of everyday questions that are asked and which all should be able to, but cannot answer...
Science
The book of wonders : $b gives plain and simple answers to the thousands of everyday questions that are asked and which all should be able to, but cannot answer...
Curiosities and wonders; Encyclopedias and dictionaries; Questions and answers; Science -- Miscellanea; Technology -- Miscellanea
A worsted fabric when finished has a clear, bright, well defined
pattern, seems close and firmly woven, and is of a pronounced dressy
effect; while woolen cloths are softer, they are more elastic, the
colors are more blended, the threads are not so easily distinguishable
and the general effect is duller.
Why Can’t We See in the Dark?
We cannot see in the dark because there is no light to see by. To
understand this we must first understand that when we see a thing, as
we generally say, we do not actually see the thing itself, but only the
light coming from it. But we have become so used to saying that we see
the thing itself that for all practical purposes we can accept that as
true, although it is not scientifically exact. Scientifically speaking,
we see that part of the sunlight or other light which is shining upon
it, which the object is able to reflect.
If there were no air about us we could not hear any sounds, no matter
how much disturbance people or things created, because it requires air
to cause the sound waves which produce sound, and air also to carry
the sound waves to our ears. In the same way, if there is no light
to produce light rays from any given object to our eyes, we can see
nothing. It requires light waves to produce the reflections of objects
to our eyes. Without light our eyes and their delicate organs are
useless. You cannot see yourself in a mirror when the quicksilver which
was once on the back of the glass has been removed, because there is
then nothing to reflect the light. We can only see things when there is
light enough about to reflect things to our eyes. When it is dark there
is no light, and that is the reason we cannot see anything in the dark.
Why Can Cats and Some Other Animals See in the Dark?
Public-domain text, read in full here on John Shaqi.
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