A text states that Hans Christian Oersted, in 1820 AD accidentally observed that Magnetic Field is produced by a current carrying conductor. The story goes by the fact that Oersted was actually demonstrating something to a class, when he saw a magnetic compass needle, placed nearby, go astray when current was passed through the wire. The point is, the discovery was ‘Accidental’.
It was actually an Italian jurist, Gian Domenico Romagnosi, who had observed this phenomenon in 1802 AD and published his observations in a local newspaper. This, however, went unnoticed by the scientific community. And now, the credit goes to Hans Christian Oersted.
In 2007 AD, I first learnt that a straight current carrying conductor produces a magnetic field around its axis in a circular way. So, when we place iron filings on a cardboard shelf and allow current through a conductor placed perpendicular to it, BINGO! You have a crudely arranged circular pattern.
I decided to give it a try : After all it is a silly experiment, the result being obvious. I was only too interested in seeing if it is really going to work… So, I met my college’s lab instructor after working hours.
“Sir….”, I stammered. “I was thinking if I could perform an experiment….. It is not in syllabus anyway”. He viewed me frantically, thought for a moment and made a promising face. I was fortunate, he felicitated the idea. So, I told him about the experiment.
Soon, I had the equipment arranged on an optical bench (sounds cool, doesn’t it?). The apparatus included a Rheostat, a battery with variable voltages, few Manganin wires (because he couldn’t find insulated copper ones).
A circuit was soon ready. We didn’t have iron filings. So, a compass was brought (fortunately), because it deflects even for slight current amplitudes. I pecked a hole on a cardboard sheet torn off from they Physics Lab Manual, A compilation of foolish questions usually asked for the Viva-Voce. It wasn’t needed at that time, because any student picked up at random from the class could furnish you with every word from the book except for things as intricate as the ISBN Code (Wonder if it has one…).
And so, I held the cardboard and the compass, parallel to the bench. My instructor held the naked wire, turned the voltage knob to a whopping 12 Volts and toggled the switch. More voltage, more current, we thought. I was checking for deflections. when my instructor withdrew his hand suddenly. The wire he held had got heated up. He had burnt his fingers.This , as we hypothesised, was due the manganin wire we used.So, soon, a new circuit was prepared with copper wires. We checked for deflections again, desperately. This time too, it was a failure. We were cracking our head as to what had gone wrong.We had forgotten to closed the switch.
Soon , there was a burning aroma.It was first presumed that someone was cooking in the adjacent apartment. Checking the circuit, I turned the Rheostat topsy-turvy only to find a Red-Hot wire! Current, was switched off, chaos was arrested.We couldn't grok where the experiment had gone wrong.We even tried changing the circuit here and there,but it made No significant yield. When all our hopes were jettisoned, we abandoned the experiment there.
The deflections were accidentally discovered, almost 205 years before, in an era where only the spelling of electricity and magnetism were firmly established. I even wonder if they had commercially made Rheostats and batteries and insulated wire.
In fact, Michael Faraday wrapped pieces of his wife’s petticoats around copper wires to insulate them because amenities such as insulated cables were not available them. But here, even with such decently good equipments, we are at a loss, even to detect current, let along trace the magnetic field lines around them. Either the text quoting that the discovery was ‘Accidental’ is controversial or physics labs in certain colleges, (where the practical examiner is taken out of the hall for break-fast and the students are provided with sheets torn off from the manual to copy) need better equipment. I wonder If Oersted's discovery , in a college demonstration, was really 'Accidental'.Guess , It needs to be changed...
It was actually an Italian jurist, Gian Domenico Romagnosi, who had observed this phenomenon in 1802 AD and published his observations in a local newspaper. This, however, went unnoticed by the scientific community. And now, the credit goes to Hans Christian Oersted.
In 2007 AD, I first learnt that a straight current carrying conductor produces a magnetic field around its axis in a circular way. So, when we place iron filings on a cardboard shelf and allow current through a conductor placed perpendicular to it, BINGO! You have a crudely arranged circular pattern.
I decided to give it a try : After all it is a silly experiment, the result being obvious. I was only too interested in seeing if it is really going to work… So, I met my college’s lab instructor after working hours.
“Sir….”, I stammered. “I was thinking if I could perform an experiment….. It is not in syllabus anyway”. He viewed me frantically, thought for a moment and made a promising face. I was fortunate, he felicitated the idea. So, I told him about the experiment.
Soon, I had the equipment arranged on an optical bench (sounds cool, doesn’t it?). The apparatus included a Rheostat, a battery with variable voltages, few Manganin wires (because he couldn’t find insulated copper ones).
A circuit was soon ready. We didn’t have iron filings. So, a compass was brought (fortunately), because it deflects even for slight current amplitudes. I pecked a hole on a cardboard sheet torn off from they Physics Lab Manual, A compilation of foolish questions usually asked for the Viva-Voce. It wasn’t needed at that time, because any student picked up at random from the class could furnish you with every word from the book except for things as intricate as the ISBN Code (Wonder if it has one…).
And so, I held the cardboard and the compass, parallel to the bench. My instructor held the naked wire, turned the voltage knob to a whopping 12 Volts and toggled the switch. More voltage, more current, we thought. I was checking for deflections. when my instructor withdrew his hand suddenly. The wire he held had got heated up. He had burnt his fingers.This , as we hypothesised, was due the manganin wire we used.So, soon, a new circuit was prepared with copper wires. We checked for deflections again, desperately. This time too, it was a failure. We were cracking our head as to what had gone wrong.We had forgotten to closed the switch.
Soon , there was a burning aroma.It was first presumed that someone was cooking in the adjacent apartment. Checking the circuit, I turned the Rheostat topsy-turvy only to find a Red-Hot wire! Current, was switched off, chaos was arrested.We couldn't grok where the experiment had gone wrong.We even tried changing the circuit here and there,but it made No significant yield. When all our hopes were jettisoned, we abandoned the experiment there.
The deflections were accidentally discovered, almost 205 years before, in an era where only the spelling of electricity and magnetism were firmly established. I even wonder if they had commercially made Rheostats and batteries and insulated wire.
In fact, Michael Faraday wrapped pieces of his wife’s petticoats around copper wires to insulate them because amenities such as insulated cables were not available them. But here, even with such decently good equipments, we are at a loss, even to detect current, let along trace the magnetic field lines around them. Either the text quoting that the discovery was ‘Accidental’ is controversial or physics labs in certain colleges, (where the practical examiner is taken out of the hall for break-fast and the students are provided with sheets torn off from the manual to copy) need better equipment. I wonder If Oersted's discovery , in a college demonstration, was really 'Accidental'.Guess , It needs to be changed...
