Talk:Photon

I did a major edit on the Photon page. As Richard Feynman himself said in his lectures to the public on QED, "photons are particles". The explanation of why they sometimes behave like waves should also be inserted into the quantum mechanics article, as it is a general feature of the theory.--Lemonpeel 13:19, 8 July 2008 (EDT)

Can you explain how light can be both a wave and a particle? --Ed Poor ^Talk 13:43, 8 July 2008 (EDT)

It is not both. It is a particle. However, due to interference possibilities of amplitudes in quantum mechanics, it sometimes behaves like a wave. I am currently trying to explain this in the quantum mechanics page.--Lemonpeel 13:58, 8 July 2008 (EDT)

Not sure how to make the first few sentences more jargon-free. There's no elementary way to explain what integer spin is--it's just one of those things. Maybe you can describe bosons as mediators of forces between matter particles. Still if someone is actually looking up photon, they should see that it's a massless particle with spin 1 somewhere on the page.--Lemonpeel 14:06, 8 July 2008 (EDT)

I seem to remember that Stephen Hawking gave a very nice analogy for the wave-particle duality in one of his books. It went something like this: A mediaeval monk travelled from England to Africa and saw a rhinoceros for the first time. When he came back, he described his observations to his fellow monks. He said, "when I looked at the front of the animal, it had a single horn". "You mean it was a unicorn?" asked the abbot. "Almost," he said, "but when I touched its skin, it felt like thick, scaly armour". "So it's a dragon?" asked the abbot.

To summarise: the travelling monk described some observations and the abbot came up with a couple of theories. The first theory was that the rhinoceros was a unicorn based on the observation that it had a horn. The second theory was that the rhinoceros was a dragon, based on the observation that it had scaly skin. Each theory was very good at describing certain types of observation, but not very good for others. The important point is that the abbot didn't know the "true" nature of the rhinoceros, but he found some nice ways to describe its characteristics. Neither unicorns nor dragons walk among us, but they were used by the abbot as models to help him understand the characteristics of the rhinoceros.

Scientists can only base their theories on observations. Some observations, like the photoelectric effect show that light behaves like a stream of classical particles. Other observations, like interference show that it behaves like a classical wave.

Scientists don't know the "true" nature of light, but they have found some nice ways of describing its behaviour. Just like the dragon and the unicorn, classical waves and particles don't really exist but they are very useful models to help us understand the characteristics of light.

I hope that explanation helps! PMorgan 19:37, 15 March 2009 (EDT)