This Month in Physics History
The interactions of electricity and magnetism are difficult to explain in all of them are unstable and disintegrate on time scales shorter than a billionth of a second. . who thought maybe Maxwell had something here) discovered radio waves. magnetism, and the relationship between the two, are fundamental to the workings of safety, electromagnets, electrical units of measure, the behavior of magnets, . They can be found in boldface in the Nonfiction Book, the Quick Reads, and/or . Students who have the same word should first compare their Word Smart. Hans Christian Ørsted was a Danish physicist and chemist who discovered that electric currents create magnetic fields, which was the first connection found between electricity and magnetism. In , Ørsted made a significant contribution to chemistry by producing aluminium for the first time. While an aluminium-iron.
Whether completely accidental or at least somewhat expected, Oersted was intrigued by his observation. On July 21,Oersted published his results in a pamphlet, which was circulated privately to physicists and scientific societies. His results were mainly qualitative, but the effect was clear—an electric current generates a magnetic force.
His battery, a voltaic pile using 20 copper rectangles, probably produced an emf of about volts. He tried various types of wires, and still found the compass needle deflected.
When he reversed the current, he found the needle deflected in the opposite direction. He experimented with various orientations of the needle and wire. Others began investigating the newly found connection between electricity and magnetism. Oersted continued working in physics. He started the Society for Dissemination of Natural Science, which was dedicated to making science accessible to the public, something he thought was very important.
In he established the Polytechnical Institute in Copenhagen. Edmonton was the first major urban centre in Canada to own its own electricity utility.
Hans Christian Ørsted
The founder of the company, Max Aitken, was initially drawn to the region by its vast hydroelectricity potential. Inthe company changed its name to TransAlta Utilities Corporation, in order to better reflect its provincial reach. A second hydroelectric dam began operations at Kananaskis Falls in Over the next two decades, a total of REAs would be established across the province.
These organizations would play a crucial role in the spread of electricity to rural Alberta. Glenbow Archives, NA Voters of Alberta narrowly reject proposal for public ownership of electricity utilities. The provincial election included a plebiscite concerning ownership of electricity utilities in Alberta.
Magnetic field - Wikipedia
Rural areas largely voted in favour of public ownership, while urban voters particularly in southern Alberta supported a continuation of private ownership. In the end, the vote was extremely close, with public ownership defeated by a mere votes. A total of fifty-two wind turbines were installed in Inthe project was expanded with the addition of fifteen new and much more powerful turbines.
- The Discovery of Electromagnetism
- This Month in Physics History
This is called induction. By simply moving a magnet through a coil of wire, one can easily detect the current flowing in the coil by using a sensitive ammeter. But if the magnet is held still inside the loop, nothing will happen. Only a changing read: Likewise, only moving charges currents give rise to magnetic fields. Unmoving charges produce only the Coulomb force. Quicktime movie of electromagnetic induction The simple demonstrations outlined above are very similar to their industrial counterparts.
An commercial electric generator is little more than a coil of wire which is rotated inside a circular arrangement of magnets. And an electric motor is little more than a current-carrying coil whose magnetic field is interacting with the field of a circular arrangement of magnets. In other words, the only difference between a generator and a motor is whether you put in force to get out current, or put in current to get out force.
The two types of devices are completely symmetric. If you turn the blade on an electric fan with your finger, then you have made it into an electric generator. I often demonstrate this fact in class with hand-held electric generators.
By turning the crank on one generator, I can send enough current through a small lightbulb to make it light up. This proves it is a generator.
But by connecting two identical generators to each other, I can also show that cranking the handle on one generator makes the handle on the other generator turn by itself, thus proving that the second generator is now acting as a motor.
In the Scottish physicist James Clerk Maxwell derived a set of equations for electromagnetism which we today call Maxwell's equations. He developed many other important equations besides these, but never mind. When physicists refer to Maxwell's equations, these are the ones they mean. While he was working on these equations, it occurred to Maxwell that if one could Similar to the way an oscillating magnetic field can induce an electric current.
Then, the oscillating electric field would produce a magnetic field. And so on, in an endless cycle. Maxwell was able to show that, if such a thing were to be created, the electric and magnetic fields would oscillate at right angles to each other one wave going up and down, the other going in and out and would travel together while shifting their energy back-and-forth as they constantly and dynamically regenerated each other.
In other words, you would have electric and magnetic fields existing by themselves, with no charges, no magnets, and no masses.
Hans Christian Ørsted - Wikipedia
Maxwell calculated that the speed of this wave would be: If we insert the values given earlier, we have: Which is the speed of light. Although this did not prove that light was the mutually perpendicular electric and magnetic wave couplet which Maxwell envisioned, it was certainly suggestive, and Maxwell did suggest that light was an electromagnetic wave.
Maxwell's picture of a light wave is illustrated below. Maxwell died rather young, at the age of 48, and it was left to others to extend his work.