Creative Books

"How?" asked Tom eagerly.
"Run your engine and propellers in a vacuum," was the prompt
reply.
"Hum!" said Tom, musingly. "Yes, that would be a simple way
out, and I'll do it, if you'll tell me how to breathe in a
vacuum."
"Oh, I didn't agree to do that," laughed Ned.
But he had spoken the truth, as those who have studied physics
well know. There must be an atmosphere for the transmission of
sound, which is the reason all is cold and silent and still at
the moon. There is no atmosphere there. Sound implies vibration.
Something, such as liquid, gas, or solid, must be set in motion
to produce sound, and for the purpose of science the air we
breathe may be considered a gas, being composed of two.
Not only must the object, either solid, liquid, or gaseous, be
in motion to produce sound, but the air surrounding the vibrating
body must also be moving in unison with it. And lastly there must
be some medium of receiving the sound waves--the ear or some part
of the body. Totally deaf persons may be made aware of sound
through the vibrations received through their hands or feet.


Pages:
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88