| Code
Number : |
8A20.50
|
Disclaimer:
|
Reprinted
by permission of Dick Berg, University of Maryland, for use on this
website.
The
demonstrations contained and referenced herein are listed for the
purposes of cataloging and describing physics demonstrations which
should be conducted only under the direction of a trained
instructional support professional or physicist. These
demonstrations are not presented for the purpose of being conducted
by persons unconnected to this Facility and/or persons not
consulting with or being supervised by the recognized instructional
support professional or physicist and his/her staff. The University
is responsible only for those demonstrations carried out using its
own equipment using established safety and scheduling policies, and
bears no responsibility for those choosing to use this source
material for their own purposes. All demonstrations described and
contained herein are public domain, and can also be found in
reference materials in libraries, bookstores, and electronic
sources.
Further
information regarding legal liability in use of demonstrations and
labs will be found on the web site Injuries
in School/College Laboratories in USA.
The
University of Iowa Disclaimers:
University of Iowa Disclaimer
All Rights Reserved.. |
| Condition
: |
Good
|
| Principle
: |
Planetary Cooling,
Radiant Energies
Kinetic Motion,
Distribution of Mass
|
| Area
of Study : |
Astronomy
|
| Equipment
: |
Metal
Ball on Rod, Stand and Rod Clamp, Bunsen Burner, Insulated Gloves,
Matches, Metal Pan, Camera and Power Supply, Oxy - Acetylene
Torch, Red-hot metal, Bunsen Burner, Matches, Insulated Gloves,
Metal Pan.
|
| Procedure
: |
This
demonstration must be started about 10 to 15 minutes before the time
to be shown. Heat the ball with the Bunsen burner until it reaches a
visible red hot. Focus the camera onto the ball with the iris all
the way open and the color balance set about halfway towards the red
end. Shut off the room lights and remove the flame and observe the
cooling process. Note the lines and spots that develop showing how
the cooling rates differ in different region according to the
structure and stresses on the sphere. When the ball is no longer
glowing visibly it can be shown that there is still a great amount
of radiating energy by touching an unlighted match to the ball and
watching it burst into flames. The Oxy - Acetylene torch will heat
the ball up much faster, however you must be careful as there is the
danger of actually melting the ball.
The new CCD cameras are very IR sensitive. Even after the
ball has quit visibly glowing in the dark room the CCD camera will
be able to see the ball very well. We also have an infrared
viewer that may be used for viewing the ball after it has stopped
visibly glowing.
Take the metal strip and hold the end in a Bunsen burner until
red hot. Turn out lights and let cool while observing visible
radiation.
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