Like kids in the amusement park, we were all astonished by the magic Professor Vales showed us during his short (1 hour 15 minutes) demonstration.

The demonstration started with the Professor showing us a miracle of an engine that worked without any fuel or any other energy supplied to it at first glance. The wheel of the engine was rotating as the engine stood on the cup of hot water. As the Professor later explained, the engine was invented by Reverend Robert Stirling, and it was supposed to replace steam engines, which were widely and commonly used in the 19th century but were dangerous and unsafe. Stirling Engine runs solely on the hot air emitted by the hot water in the cup. The physics principle that this engine utilizes is temperature differential.

There was one more of this kind of engines standing on the table and powering a fan. This one stood on two legs that were thrust into two cups, one of which was filled with hot water and the other one with cold water. The temperature differential plus the difference in the materials, from which the two legs were made, resulted in energy being created. This types of engines, as Professor Vales explained, produce only a little power and so are practically almost useless. The only industrial applications of the engines are that they power fans on submarines, where they quietness and energy saving features are fully appreciated and needed. Other than that, temperature differential engines can be found only in physics lab rooms.

The demonstration continued with the Mendocino Solar Motor. This was, in a sense, an extension of our solar cell activity combined with the generator lab we also performed earlier. The engine looked like a simple DC (direct-current) motor, but had no external power supply connected to it. When the professor directed a flashlight at the motor, it started rotating. What the motor did then was that it converted solar energy into electricity, which due to the application Faraday’s Law and magnetism laws made it rotate.

After that, Nicola Tesla’s coil came. If everything that has been shown before looked amazing, then the Tesla’s coil was absolutely hilarious. It lit up the lights without being connected to them. Tesla’s coil electrified not only the air around it but also us as we observed flashes of electricity coming out of it. Then the Professor did what none of us would ever do by ourselves: Professor Vales touched the electric field of the Tesla’s coil with a wire. As he explained the electricity at such a high frequency of 1000kHz produces “skin effect,” which allows us to touch it without any harm being caused to us.

Professor Vales did not get tired from amusing us. The next thing he did was that he took the copper tube and asked us what was going to be the acceleration of the magnets as they flew through the tube, falling. The answer was unequivocal as all of us knew the acceleration due to gravitation is 9.8 m/s^2. But what happened next, from our point of view, could not be explained by anything but magic. It took nearly 10 seconds for magnets to fly down 2-meter tube. The Professor told us that this was because the rare-earth magnets caused an electric current in the tube while they flew down, and this current interfered with the magnetic field of the magnets and caused an upwards force, which made the magnets slow down as they fell.

Finally, the demonstration concluded with the repulsion coil, which made the aluminum coil fly all over the classroom.

One important point that this demonstration has emphasized is the variety of sources of energy. In the today’s world, it almost seems like we are limited to gas and oil regarding energy production. But that is not true. If 200 years ago, Reverend Robert Stirling invented his Stirling engine that converts temperature differential into power, nowadays with all the technologies at our fingertips we can come up with much more efficient and cleaner ways of obtaining energy than just burning fossil fuels.