Isn't a wave what something does and not what something is?

[revv]

Main Question or Discussion Point

When people say light is a wave what do they mean? Isn't a wave what something does and not what something is?

 

[Nugatory]

Natural language is often used imprecisely. It's just a lot easier to say "light is a wave" than "certain aspects of the behavior of light are accurately predicted by the wave equation".

 

[sophiecentaur]

When people say light is a wave what do they mean? Isn't a wave what something does and not what something is?

I could go along with that. In Physics, people are reluctant to talk about what something 'is' because all we can ever describe with some certainty is what it 'does'.
PF is constantly being asked what things 'really are', in one context or another (photons, electrons, momentum etc.) , and there is never a conclusive answer. As far as Physics is concerned, it really doesn't matter as long as you can make predictions and verify theories by experiment.

 

[Jehannum]

It seems that, for many physicists, physics is closer to engineering than to philosophy.

It's understandable - and laudable - when children want to know the true nature of things. Unfortunately, they may be disappointed when they realise there isn't a simple visible/audible/textural picture for things out of the limited realm of human senses.

But I think there's a place for interpretation in physics: for metaphors and mechanical models even in the abstract realms of the quantum world. As long as you know it's just an aid to visualisation, that is.

 

[sophiecentaur]

As long as you know it's just an aid to visualisation, that is.

Yes. As long as you know, it's OK for your. The problem is that teachers and broadcasters do not actually know that. They present metaphors to kids as if they are fact (many teachers do not know better). That helps no one in the long run.
Society took centuries to accept that 'childhood' is a useful phase for nearly everyone. The pendulum is swinging the other way now and kids are exposed, earlier and earlier, to issues that they cannot deal with. Science is part of this movement.

children want to know the true nature of things.

I would actually not agree with that. Children want to be presented with models of the world, (Scientific, social and moral) with which they can cope. In a few cases, they can move on to more sophisticated models but, if you look at the more popular newspapers and TV, you can't not be aware that most people actually dont't want a part of those more formal processes. They want a statistic about how far away the nearest star is and not the mechanism that keeps a Galaxy the way it is. No wonder that many adults look back on most of their education as a blur and boring - they have been preached at by teachers who were convinced that every class member was going to be a Scientist, Mathematician, Linguist.

 

[jtbell]

But I think there's a place for interpretation in physics: for metaphors and mechanical models even in the abstract realms of the quantum world.

A specific interpretation may give a physicist insight or intuition into a theory which helps him develop the theory further, even though in the end his findings can also be "explained" using the other interpretations of the theory.

 

[sophiecentaur]

A specific interpretation may give a physicist insight or intuition into a theory which helps him develop the theory further, even though in the end his findings can also be "explained" using the other interpretations of the theory.

I'd go further than that. Einstein claimed to have used all sorts of pictures of everyday events to help him through his groundbreaking discoveries. But they were 'personal' and he never sold them as 'truth'. A genius, communicating with non-genius but well informed people can often get the ideas across with metaphor but none of 'us' believes that the metaphor is anything but that.
Children, on the other hand, will take the animations and moving models of EM waves as literally as a working model of a steam engine. That is also true for a vast majority of the population - including quite a few PF contributors.

 

[Jehannum]

I would actually not agree with that. Children want to be presented with models of the world, (Scientific, social and moral) with which they can cope.

I'm not so sure this is always true. I remember wanting to know "what is time" as a very young child and being disappointed with the books in the local library (pre-World Wide Web) which just focused on clock mechanisms etc. I was fired up on Doctor Who, so that stuff just seemed dull. I would have loved a mind-blowing explanation.

And there's the well-known story of the kid who asks "but why?" to every explanation he's given until the teacher runs out of knowledge. The only answer possible is "because it's the way things are".

However, you're right in a sense. I remember having quite a few perfectly concrete questions my (primary school) teachers couldn't answer: Why is the air shimmering above that radiator? Why does that plastic box lid have rainbow colours in it? Why do I see dark lines between my fingertips when I bring them together near my eye?

Perhaps having a model with which we can cope really means having something to fill in the gaps in our mathematical ability. Mathematics seems to be the ultimate, endlessly self-generating model.

 

[Mark44]

Isn't a wave what something does and not what something is?

From the linguistic perspectie, many words in English have different meanings, depending on the context in which they are used.

If you go to the beach you can see a wave crashing on the shore. If you see a friend, you can wave to him or her. In the first sentence, "wave" is a noun (what something is), and in the second sentence, "wave" is a verb (an action -- what something does).

 

[sophiecentaur]

Perhaps having a model with which we can cope really means having something to fill in the gaps in our mathematical ability. Mathematics seems to be the ultimate, endlessly self-generating model.

You are right about the Maths. BUTTTTTT talk to any random person in the pub and ask them how they get on with Maths. That's the stumbling block for the majority of the human race and Physics.
Funny thing is that most people have a very humble attitude to some branches of Science, Medicine, Engineering but they seem to reckon Physics can be described with a wave of the hand.
I blame the broadcasters, myself.