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Mechanical Resonance on Atomic Size Scalee
Name: Andy
Status: student
Grade: 9-12
Country: United Kingdom
Date: Summer 2011
Question:
I'm thinking about resonance. In particular about the
resonate frequency of products (eg the singer breaking the glass by
singing a note at
the resonate frequency of the wine glass).
I understand the theory
of resonance, but was wondering what happens if you resonate a an
element in gas form - eg oxygen - in a fixed volume box/container?
What
happens to the
oxygen, does it break down? Or polarize? Is heat produced? If heat
is produced what happens when you stop resonating - does it get
very cold as a result?
Replies:
Andy,
Temperature is defined as molecular vibrations at an atomic
level. So yes, if you were to vibrate an oxygen atom, that, by
definition, would be raising its temperature. Conversely, one way
scientists cool atoms to extremely cold temperatures (very near
absolute zero), is to hit them with lasers to stop those vibrations. I
suggest you read about the molecular definition of temperature (or if
you are ambitious, read about quantum thermodynamics) for more
information.
Hope this helps,
Burr Zimmerman
In order to have a resonance, it is necessary to have a restoring force acting on the target -- the forces holding the glass together in your first example. Unless the pressure of a gas is very high, there are no restoring forces to overcome the impinging force. Now everything has its exceptions. If the gas is at sufficiently high pressure that it is a liquid there are restoring forces, but these behave by forming bubbles if the impinging pressure exceeds the vapor pressure of the liquid at the temperature.
But that is an extreme example. If the gas is contained in a box, the box can resonate, and the gas will respond accordingly. But that really is not the gas resonating, it is the gas responding to volume changes in the box.
To give a complete answer to your question, the conditions of the "experiment" would have to be more precisely defined.
Vince Calder
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