Fun with the home made Van de Graaf machine

 

 
 
Below are pictures of the first trial.
Results:

Over one inch visible spark,

Electrons can be heard jumping to objects up to 7" from sphere,

Hair raising sensation felt as much as 13" inches from sphere.

 

Materials:

Press board "base platform" and "motor housing."

Model airplane motor and 12 volt battery. [Any motor to drive the pulley will work]

3 foot 4" pvc sewer pipe to make your column tube

pvc pipe for bottom pulley

rubber band

nylon roller for top pulley with nylon pvc spacers

copper ground wire and brush 1/8" from bottom pulley

collector brush 1/8" from top pulley with copper wire leading to sphere (space 1/8")

13" plastic hamster ball [surface crevices smoothed with Bondo and painted with metallic copper paint]

Housing and pipe painted and coated with polyurethane

 

Caution:

 

Electrons accumulate around this machine. Do not use near computer equipment.

 

Building the Van de Graaf (VGM) Machine:

  1. Build the wood "motor housing" on a wood "base platform" to fit the motor. (See pics below)

  2. Cut a wood "top plate" to fit on top of the motor housing.

  3. Cut a hole in the "top plate" to fit the column tube into snugly.

  4. Cut a hole in the top of the "motor housing" 1/4" smaller than the top plate hole. This will serve as a platform for the column tube.

  5. Place cut pvc pipe onto motor [you will have to modify according to the motor setup]

  6. To make top pulley, slide nylon roller onto a 16 penny nail that is ground down on both ends to make an axle. Slide nylon spacers on both sides of the nylon roller.

  7. Note: taper the sides of the rollers slightly so that the rubber band will position itself in the middle and not slip to the edge.

  8. Cut a V notch into opposite sides of the top of the "column tube" to fit the roller axle (a cut nail).

  9. Fix motor into housing so that pvc roller is centered with the top plate hole.

  10. Measure the length of a rubber strip to fit around top and bottom rollers. Cut ends and super glue them together to form a giant rubber band. Place over the rollers. It should stretch onto the rollers so that it does not touch the sides of the column when in motion.

  11. Make two brushes by soldering cut strands of wire onto a copper wire. The length of the brushes should match the rubber band width.

  12. Attach the bottom brush to motor housing with a bolt, nut, and washer.

  13. Bend brush to about 1/8" from rubber band.

  14. Attach top brush to "column tube" with bolt, nut, and washer. Copper wire should lead from brush to the sphere through holes in the "column tube."

  15. Purchase a plastic pet hamster ball, fill holes and crevices with Bondo, and paint with metallic paint. I used copper paint.

  16. Disassemble and paint the base, motor housing, and column. After painting, coat with polyurethane.

  17. Reassemble and turn it on!

 

 

  

Wood housing for motor and roller

  

Motor mounted to base platform
 

    

Wire strands from a #14 wire cut, bent, and draped over copper wire.

  

Solder the wires onto the copper wire.
 

    

Attach brush to column tube and lead copper wire through column to outside.

  

Place sphere on column and bend wires to touch sphere.

 

Experimenting:
  1. Try different spheres, length of column, brush sizes, metallic paint, rubber band materials, different positions of brushes.
  2. Troubleshooting:
 
 
Having fun:
  1. Look for eventual accumulation of dust on the VGM due to charged particles.
  2. Feel your hair pulled toward the sphere
  3. Listen for electron wind as you bring a screwdriver, hand, or object close to the sphere
  4. Tape 12" string or tissue to top of sphere, then watch it follow your hand.
  5. Notice that after turning off VGM, paper tissue is still charged. Discharge it by touching the sphere.
  6. Tie a nut to the end of a string and bring it close to the sphere
  7. Put your hand on the sphere and watch your hair stand up
  8. Place hand on sphere and hold hands with friends
  9. Hold a flourescent light bulb in one hand while touching the sphere.
  10. Make aluminum foil hats for the sphere and turn VGM
  11. Blow soap bubbles at the VGM sphere
  12. Touch sphere while wearing the flashing tennis shoes
  13. Tape an aluminum foil cone to the top of the VGM and watch for St. Elmo's fire at night
  14. Make an ion beam gun by taping a paper clip to the sphere.
  15. Float a balloon toward the VGM.
  16. How long a spark can you get from your VGM? The longest spark I have gotten so far is two inches.
 
Interesting observations

  1. Experimenting in the dark will give you more interesting visual observations.

  2. In the dark, I was able to see the tip of my finger nails light up (St. Elmo's Fire) as I held them near the sphere.

  3. In the dark, I could see electrons glowing from objects near the sphere surface.

  4. You can get bigger sparks jumping to a dryer arm than a sweaty palm.

  5. We consistently got an eight inch spark playing with the help of the string.

  6. You get better results if people do not "crowd" the VGM and objects are not near the VGM.