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EXPERIMENTS AND PARADOXES OF ELECTRICITY AND MAGNETISM GUIDO PEGNA Dipartimento di Fisica Università di Cagliari [email protected] http://www.pegna.com We present here some simple apparatus and experiments The goal is to stimulate curiosity, the wish to understand, the attitude to built self made apparatus, with the exercise of rationality creative skills, good sense, concreteness. TO SEE THE VIDEOS PLEASE CLICK ON BLUE “CLICK” THE MISTERIOUS OSCILLATING CIRCUIT CLICK Rlc2_osc.wmv The circuit Why it oscillates at very low frequency? 100 € to whom who gives the solution! (Write it to [email protected]) A series of two lamps and two switches One switch lights one lamp The other switch lights the second lamp Both switches...both lamps Where is the trick? More A lamp short circuited by a thick copper conductor copper tube LOOK AT THIS PARADOX: CLICK Is that a paradox? What is contained in the base? One more interesting phenomenon Levitation. A close-up view... A small magnet levitates without any external energy supply What is this? Magnet And now: a very interesting apparatus: a completely static electrostatic machine Look at the following video... THE COMPLETELY STATIC ELECTROSTATIC MACHINE high voltage terminal Please note the effect on the electroscope and on the electrostatic motor without direct connections in the following video RUN! CLICK One more interesting experiment AN ELECTROMAGNETIC GUN CLICK WITH AN OTHER PROJECTILE CLICK A strange motor without coils, brushes N pole magnet + contact S pole - RUNNING ON A 1,5 V BATTERY CLICK An extraordinary technological exploit The ultracapacitor: note the value of the capacity WHEN FULLY CHARGED THE ULTRACAP MAKES THE MOTOR RUN FOR DAYS CLICK A very clear demonstration of the behaviour of inductors and capacitors Lamp Lamp Lamp Inductor Capacitor Resistor Inverter diagram The lamps are connected in series with the resistor, the inductor and the capacitor and indicate the current through those items when the voltage is rapidly inverted CURRENT THROUGH THE INDUCTOR CLICK AND THROUGH THE CAPACITOR CLICK CURRENT THROUGH BOTH INDUCTOR AND CAPACITOR CLICK A revolutionary table top apparatus for the determination of the speed of FREE propagating light in 60 cm measuring base Immediate set-up, nothig to aligne Transmitter: Laser modulated at 450 MHz Control unit Graduated scale Synchcronous receiver sliding on the guide pointer THE SPOT OF THE LASER CLICK THE MEASURING POINTS ARE INDICATED BY AN AUXILIARY AUDIO SIGNAL CLICK Direct determination of the refraction index in only 10 c.c. of a liquid Tray Scale A small simple experiment To demonstrate the thermoelectric effect copper Costantan Coil Compass AND A GAS LIGHTER… CLICK and many other intriguing experiments All these apparatus are original creations of Prof. G. Pegna of the Dipartimento di Fisica Università di Cagliari, Sardinia, Italy. Please take a look to many other experiments and exhibits in: http://www.pegna.com Thank you! CIENCIA EN ACCION Cagliari, Italy, may 2011