Table of Contents

45. Electroscope

An electroscope is constructed from a pop can taped to a styrofoam cup. Thin strips of aluminum foil are hung from the pull tab. Electically charged objects can then be introduced and studied. . (TOC)

(TOC)

45. Charging by Induction

A charged ebony rod is placed in proximity to an electroscope. The induced charge causes the leaves to separate. (TOC)

(TOC)

46. Coulomb's Fountain

A Styrofoam cup, half-filled with puffed rice, is placed on top of a Van de Graff generator. When the generator is turned on a fountain of charged particles is made. (TOC)

(TOC)

47. Oersted's Discovery

The current generated by the Genecon generator creates a magnetic field that interacts with the compass needle. (TOC)

(TOC)

48. Lenz's Law

A neodymium magnet is dropped into a copper pipe. The falling magnet (changing magnetic field) induces a current that circulates through the copper pipe. The direction of the induced current is such that the induced magnetic field opposes the change in magnetic field of the falling magnet.  The magnet floats in mid air. (TOC)

(TOC)

49. Capacitance

The electrical energy generated by the Genecon generator can be stored in a 1 Farad capacitor, and then be used to perform short term tasks. (TOC)

50. Transformer

The voltage generated by a Genecon generator (~6 V) can be stepped up sufficiently to light a 60 V Neon lamp using a buzzer and a 1:10 step up transformer. (TOC)

51. Speaker

A coil, made from magnet wire, and a magnet are taped to the bottom of a plastic drinking cup. When a hand generator is hooked up to the coil, the fluctuations in the generator current can be heard. (TOC)

52. Gauss' Law

Place a florescent light source next to a radio tuned to a weak AM station. Once a wire cage is placed over the radio the static will go away. (TOC)

53. Force on a Current Carrying Wire I

A thin 70 cm long strip of aluminun foil is taped at both ends to a stand. Applying a current (8 V) to the loop causes the foil to repel. (TOC)

(TOC)

54. Force on a Current Carrying Wire II

A thin 70 cm long loop of aluminun foil is taped to a stand. Applying a current (8 V) through the loop causes the foil to attract. (TOC)

(TOC)

55. "Magic" Motor***NEW!***

A neodymium disc magnet is suspended from the positive end of a 1.5 V battery with a wood screw (or nail). When current is applied to the side of the magnet, with a wire from the negative end of the battery, the magnet spins with high angular speed. (TOC)

(TOC)

56. Mystery Motor ***NEW!***

A neodymium sphere magnet is suspended between the points of two wood screws. As current passes from the side of the magnet to the bottom, the magnet spins. (TOC)

(TOC)

57. Generator Efficiency

The efficiency of genecon generators can be compared by hooking twotogether, and calculating the ratio of input turns to output turns. (TOC)

(TOC)

58. Wire Resistance

The electrical resistance of a section of nichrome wire is shown to be a function of wire length. (TOC)

59. Magnetic Compasss

A piece of thread is tied around a neodimium magnet. The magnet rapidly aligns with the earth's magnetic field once suspended.

Neodimium magnets (salvaged from an obsolete computer hard drive) are placed on either side of one's hand. The magnetic field is strong enough to hold the magnets firmly in place when seperated by the thickness of one's hand. (TOC)

Neodimium magnets are strong enough to attract the trace amounts of iron in American currency. (TOC)

Using an obsolete TV or computer monitor, the image on the screen can be displaced when a magnet is moved nearby. From this, one can reasonably infer that the magnet is deflecting the electron beam inside the picture tube. (TOC)

ModernPhysics

Sand the top side of the homemade electroscope (Demo #45) exposing the bare aluminum. Negatively charge the electroscope with a balloon that has been charged. Shine a flashlight and/or long-wave blacklight on the electroscope and it remains charged. Shine a UV-C germicidal hand sterilizer on it and it discharges. Placing a glass plate between the UV-C source and electroscope will block the UV and prevent the electroscope from discharging.. (TOC)

64. Solid State Electronics

A light-emitting diode is connected in series with a 200 ohm resistor to a three volt source. The one-way nature of conduction is then shown. (TOC)

(TOC)

65. The Peltier Effect

The absorption or emission of heat energy when electrons move from one state to another across dissimilar semiconductor junctions is known as the Peltier effect. Connect the Genecon generator to a commercially available thermoelectric device. Turn the handle one way, and the plate heats up. Reverse direction, and the plate cools down. (TOC)

66. Quantum Numbers

An analogy between the number of turns in a Mobius strip and the principle quantum number can be made. The analogy can also be extended to the DeBroglie wavelength. (TOC)

Chemical Reactions

67. Latent Heat of Fusion

A clear plastic pouch of sodium acetate releases latent heat upon crystalization. (TOC)