PIRA Code(s): 3A10.40 Set up time:none Operation: Push the pendulum so that it swings back and forth at an angle of about 0 º. Then, slowly increase the angle, and watch the frequency decrease. For a more effective demonstration, start the pendulum at a relatively high angle, and then decrease the angle of the plane of oscillation so that the frequency of the pendulum will increase over time. Physics and Science Concepts: Oscillations Safety: None
PIRA Code(s): 3B30.30 Set up time:10 minutes (5 minutes to pump the bell jar) Operation: Plug in the pump and attach the clear tube of the pump to the valve. Turn the switch on the power supply to ascertain that the alarm is working properly. Then, pump out the air inside the bell jar. It will take about 5 minutes to obtain a low enough air pressure so that the alarm will not sound. Turn the alarm on and slowly open the valve, allowing the air pressure in the bell jar to increase. The sound of the alarm will also gradually increase. Physics and Science Concepts: Sound waves Safety: A glass jar containing a vacuum can be extremely hazardous if broken.
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): 5A50.30 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): 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): 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): 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.