Category Archives: Electricity & Magnetism

Electrostatic Twirl

Demo Code: EM-A-ET
Pira Index: 5A 20.10

Video link: Electrostatic twirl

Lab Equipment Direction
1. 3 PVC pipes (exactly alike)

2.  Lab Stand

3.  String

4. Short lab Pole

5. 90 degree clamp

6. Paper towel

7. Plexiglass charging rod (same size as PVC)

1.  Suspend one PVC pipe on a string as shown and loop the straight string over the lab pole. 2.  Charge the suspended pipe by rubbing it with paper towel.3.  Charge another pipe and bring it near the suspended one. Observe.

4.  Charge the 3rd pipe and bring 2 charge pipes near the suspended one. Compare the effect of two pipes with the effect of only one pipe.

5. Charge the acrylic rod w/the paper towel and watch it attract the hanging PVC pipe.

Suspended Cart

Demo: ME-J-SC
Pira Index: 1J 30.10

 Lab Equipment  Directions
  1.  lab stand
  2. C-clamp to clamp lab stand to cart
  3. lab pole
  4. telescope clamp
  5. triangle 3, 4, 5 ramp
  6. 2 pulleys
  7. 2 right angle clamps
  8. small cart (mass = 250g)
  9. 2 strings
  10. hooked weights (200, 100, and 50)
  1.  Set the apparatus up as shown, hang weights so that one string runs parallel to the ramp and the other makes a 90 degree angle with the ramp.
  2. Slide the ramp out from under the cart to show that the normal force and the tension force balance the gravitational force on the cart.

Tesla Coil

Demo: EM-N-TC
Pira Index: 5N 20.50

 Lab Equipment  Directions
  1.  Tesla coil with grounding wire
  2. Fluorescent tube
  3. Neon (spectra) tube
  4. Wood to turn off coil (meter stick)
  1.  Place Tesla coil away from all metal objects and turn it on.
  2. Holding the ground wire, bring the end of the wire near the top of the Tesla coil to draw a spark. As you pull the ground wire away from the coil, the longer the spark discharges.
  3. Attach ground wire to the end of the neon or fluorescent tube. Keeping hands away from any metal on the tube, bring the tube near the top of the coil and observe the effects.
Turn off Tesla coil with wood only.


Light Spectra

Demo: EM-N-LS
Pira Index: 5N 30.10

 Lab Equipment  Directions
  1.  2 60 degree prisms
  2. 35mm projector
  3. Projector cart
  4. Optical slit slide
  5. 2″ x 4″ x 6″ block
  6. Screen or wall
  1.  Set up as shown in figure with prism #1 in place on the block.
  2. Turn on the projector and if a rainbow does not show on the screen, rotate prism #1 either to the left or right until a rainbow appears.
  3. Put prism #2 in between prism #1 and the rainbow beam, and you should see again a beam of white light; if not, rotate prism #2 either to the left or right until white light show up again.


Visual AC

Demo: EM-L-VA
Pira Index: 5L 30.21

 Lab Equipment  Directions
  1.  Neon lamp on a cord
  1.  Swing the cord around in a circle and see that the light is actually not constant, there are light and dark bands.
  2. Observe the light standing still. Persistence of vision leads you to believe that the light is constantly lit.