Ciwan wrote:Thanks, I can't help but feel a little sad not being able to grasp the 'idea' of an electron !!

How do we know about their charges ? I assume our senses here also fail for Protons and Neutrons .. They too aren't little round balls right ?

So how do we know that an Electron (which we don't really know the looks of) has a negative charge ?

Thanks

Robert Millikan did an experiment to determine the charge.

The_Metatron wrote:

Ciwan wrote:Thanks, I can't help but feel a little sad not being able to grasp the 'idea' of an electron !!

How do we know about their charges ? I assume our senses here also fail for Protons and Neutrons .. They too aren't little round balls right ?

So how do we know that an Electron (which we don't really know the looks of) has a negative charge ?

Thanks

Robert Millikan did an experiment to determine the charge.

Which type of charge is called negative and which is positive is completely arbitrary. It is an accident of history that we say electrons have negative charge and protons positive. We know there are two types of charge and that charges of the same type repel each other and charges of differing type attract.

Ciwan wrote:Hmm I'll be lying to you if I said I now understand it.

The reason Electrons came to my mind and not Photons is:

1) I do not have a clue what a Photon is. It was never taught to us in High School GCSEs' Physics. All I know is that a Photon is a particle of light (first proposed by Einstein I believe). I'm not sure whether it has a Charge or not, I'm not sure whether it has a mass or not, and finally I'm assuming that it moves in straight line, since it is called a particle and not a 'wave'.

The nature of light has been argued about for thousands of years. Galileo actually upset the Jesuits by making certain arguments on the nature of light in his book 'The Assayer'. His ideas in this book were clearly descended from the philosophy of Democritus, whose atomism was anathema to the Catholic theologians of the time. It directly challenged the eucharistic doctrine of transubstantiation, which relies on the philosophy of substance and accidents, which is contradicted by atomism. This was made an absolute dogma of the church of Rome in response to rampant heresy, particularly the protestant movement. Some historians think that Galileo's atomist tendencies were considered far more dangerous than his Copernicanism. Later Isaac Newton like Democritus argued that light must be corpuscular in nature. It wasn't long before phenomena of light, such as diffraction and interference were discovered. These are clearly understood to show that light behaves like a wave. Eventually it was realised there was at least one major problem with the wave model of light, namely the ultraviolet catastrophe. The solution worked out by Max Planck was that light must be radiated in discrete packets with energy proportional the the frequency. Einsten confirmed this idea with his explanation of a phenomena of light known as the photoelectric effect.

In the end electrons or light are what they are. Our ideas about them are just models used to explain observed behaviour of nature. The phenomena are the territory whereas our wave/particle explanations are akin to a map. A map is not the territory but maps are still useful when you are lost . If your map is good enough you might even be able to use it to develop the technology for such things as computers and the interwebs. .