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): 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): 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.