PIRA Code(s): 5A20.20 Set up time:1 minute Operation: Charge the rod by rubbing it the through the cloth provide or on your shirt. Hold the rod near a pith ball. The two balls will repel each other. The PVC gives a positive charge and the acrylic rod gives negative charge. Physics and Science Concepts: Electrostatics, Coulomb’s Law Safety: None
PIRA Code(s): 5A22.22 Set up time:3 minutes Operation: First, show the electroscope in resting stage. Then, charge a rod or other material by rubbing the object in a cloth. Place this near the plate of the electroscope and observe the deflection of the needle. To keep the needle deflected, scrape the plate with the charged object. A decrease in deflection occurs when an oppositely charged object is placed near the plate. Physics and Science Concepts: Electrostatics Safety: None
PIRA Code(s): 5A50.10 Set up time:2 minutes Operation: Place the four (two large, two small) balls on the poles in the front about 1 inch apart. Turn the crank. Physics and Science Concepts: Electrostatics Safety: Do not touch any metal portions of the generator
PIRA Code(s): 5A50.30 Set up time:10 minutes Operation: Plug in the generator. Turn on the rocker switch and adjust speed using potentiometer on the base of the Van de Graaff.
Other suggested uses include combining this with other electrostatic demonstrations found under a 5A50 heading. Also, throwing packing peanuts or taping strips of paper to the Van de Graaff are popular demonstrations. Physics and Science Concepts: Static Electricity, Friction Safety: The rod works best on dry days with the blue wig. Care should be taken when operating. Do not approach the generator while it is running. Use the grounding rod to discharge.
PIRA Code(s): 5B30.20 Set up time:5 minutes Operation: Use the Van der Graaf or Wimshurst generator to charge the ovoid. Touch a proof plane to the pointed end of the ovoid and another to the spherical end. Place the proof planes on the electroscope plate. The deflection will be greater from the proof plane that touched the pointed end. Physics and Science Concepts: Electrostatics, Surface Charge Density Safety: Electroscope can be obtained from demonstration number 5A22.22.
PIRA Code(s): 5C10.20 Set up time:none Operation: Charge the plates using the Van de Graaff. Disconnect wire going from top of sphere to fixed plate at plate end. Change the spacing of a charged parallel plate capacitor while it is attached to an electroscope. Observe changes in electroscope pointer. Physics and Science Concepts: Capacitance Safety: Electroscope can be obtained from demo 5A22.22. The Van de Graaff can be obtained from demo 5A50.30.
PIRA Code(s): 5C30.40 Set up time:5 minutes Operation: Jars can be charged with either the Wimshurst generator (5A50.10) or Van de Graaf generator (5A50.30). Charge Leyden jars in parallel and discharge, charge in parallel again and connect in series before discharging. The intensity of the sparks as well as their duration is much greater for the series connection. Physics and Science Concepts: Electricity and Magnetism, Capacitance Safety: Do not touch the charged capacitor. Make sure the jar is discharged before storing or touching.
PIRA Code(s): 5E40.20 Set up time:1 minute Operation: Pour sulfuric acid into the glass container. Wait 5 minutes for the reaction to take place between the dissimilar metals. Place the voltmeter on the overhead and display the voltage generated in the cell. Physics and Science Concepts: Electromotive Force and Current Safety: Be careful around acid. Gloves and goggles should be worn when handling acid.
PIRA Code(s): 5H10.30 Set up time:3 minutes Operation: Place the magnet under the piece of paper and on the overhead. Sprinkle iron filings over the magnet and the filings should align with the magnetic field. Physics and Science Concepts: Magnetic Fields and Forces Safety: An overhead can be obtained from demonstration 9A36.10.
PIRA Code(s): 5K10.20 Set up time:1 minute Operation: Hook the leads from the galvanometer to the induction coil. Place a magnet in front of the coil. Turn the crank and the needle on the galvanometer should move. The connection between the galvanometer and the loop changes polarity every half turn. Physics and Science Concepts: Electromagnetic Induction, Electricity and Magnetism Safety: Magnet is extremely strong so do not place metal objects near it.
PIRA Code(s): 5K20.30 Set up time:2 minutes Operation: Set up the apparatus so that the silver pole sticks above the platform a few inches. Place a full ring around the tube and turn the apparatus on. This will make the ring jump into the air. Turn off the machine then, place the split ring around the pole, turn on the machine and this will not do anything. Resistive heating can be demonstrated by holding the full rings down and feeling them heat up. Next, turn off the machine, place the copper coil around the pole and press down on the copper rod sticking off the coil to create sparks. Also, place the light bulb circuit ring against the flat top part of the pole and watch it light up. Physics and Science Concepts: Lenz law, Electromagnetic Induction, Eddy Currents Safety: Do not place apparatus directly under a light. Do not stand above machine when the rings jump. Do not hold the full ring down too long, you may get burned.