Because when it had any, the warmth of the sun heated the atmosphere to the point where the average speed of the gas molecules exceeded the escape velocity for a body with the moon's mass and size. So, little by little, they escaped.
A warm copper wire will have more conductivity
<span>Pitch and frequency are more or less the same thing - high pitch = high frequency.
The freqency of vibration of a string f = 1/length (L) so as length decreases the frequency increases.</span>
