HISTORICAL INSTRUMENTS OF SCIENCE & TECHNOLOGY FOR SALE & LOAN FOR PROPS IN SCIENCE TV

Jim & Rhoda Morris
http://www.scitechantiques.com 
9 Morningside Rd. Wakefield Ma. 01880 ---call 781 245 2897> To Email Us For Availability and Prices jcm@scitechantiques.com
 Don't forget to Click on the Thumbnails to get  larger photos in the collections below.

 

Click on the photo to see a  NASA discussion of plasmas and their importance and our additions of  photos and drawings to make a better connection with Basement laboratory apparatus and the Pie in the sky.
Scroll down to see a home  movie of a basement  Plasma interacting with a magnetic field.

 

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A Plasma in a Bottle  
The video is of a laboratory plasma generated by in  "electric gas discharge tube" filled with air at a pressure of 0.1 mm. or at 1/10,000 the pressure at sea  level. This plasma is contained in a glass tube about 1 inch inch in  diameter and about 10 inches long. At each end of the tube are vacuum tight electric connections, called electrodes, to the gas inside of the tube. The electrodes are connected to a high, 15000 volts maximum, transformer operating at 60 cycles second with a current capacity limited to 0.030 amperes (30 ma,).

How is the plasma generated/ made?
When the power supply is turned on electrons will be forced to leave the negative electrode with a force of several thousands of volts. They will be accelerated into the gas by the power supply voltage at such a velocity that when they come into contact with air molecules they will hit it with such force they will knock off some of the outer orbiting electrons of these molecules. They in turned will be accelerated by the voltage of the power supply. They in turn will run into more air molecules  knocking of their electrons off. This process will  repeated itself  until there is a substantial electron current flowing  through the  now ionized air molecule in the discharge tube. Behold we have our laboratory plasma. Interesting enough the electrons will reach a temperature of thousands of degrees Kelvin, but the heavier particles will be  barely above room temperature! These type of plasmas are found in fluorescent lamps. The gas inside is not air but noble gases and mercury vapor. But that's another story.

The effect of a magnetic field on our plasma
When one brings a magnet close to the discharge it separates it into two arched discharges! one bending away from the magnet and the other bending toward the magnet showing that plasmas have  magnetic prosperities field interacts with the magnetic field of the discharge which pushes the flow path of the of the electrons away or toward the magnet as it is brought close to the discharge. This bends  the column away or toward the poles of the magnet depending of the direction of the flow of the current. If the discharge is replaced by wire carrying the  flow of electrons, and the a current alternating is changing direction  with a period of  seconds   it will force the wire to swing back and forth just as the discharge does.).     This shows that plasmas have magnetic fields associated with them and  these fields interact with other parts of the plasma and with other plasmas in the neighborhood. The movie takes a few minutes to download  and runs for about 30 seconds.
Click here to see the short movie of our laboratory Plasma generated with an electric discharge interacting with an external magnetic field.  The file format is    WMV

What about the light given off by the plasma
 

 Below is a short movie of our laboratory Plasma  

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Important Questions to Answer When putting  the Presentation Together 

How did I get interested in this project?  Glass Blowing? Art? Beauty? Chemistry course? What Else?
What is the object of this program?

What is a plasma and why should we know about them?
Why is it important to know about plasmas?
Where are they found?

A in Nature
B in the home
C in medical field
D in industry
E in the military
F in the laboratory
G in toys
H in advertising
I in TV sets and computer displays
J In Lasers

Can you show pictures of them being used?

How can one make a plasma?
What equipment is used by scientist and engineers to study  plasmas?
What would be the  simplest equipment that can be used to study plasmas?
Where would be some good sources of information about plasmas?

 Gas discharge tubes and  plasmas, voltmeters ammeters, spectroscopes, light meters,

 How does one control a plasma, in the laboratory,  to study it?

 What would be the things about a plasma that one could  easily  measurer to understand  plasmas?

1, What are they made of?
2, Can one see them?
3, What are their electrical characteristic?
4, Are they magnetic?
5, What do they weigh?
6, Are they fragile?
7, Can you bend them?
8, How long do they last?

What would be a good title for this project?

 

3/1/2005 10:49:49
 

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