1. Sep 22, 2009

### Vincit

hey, i'm 15 years old, and i'm still going to high school:) But Physics has been my main subject of study for a few years now(since i was 7 to be precise) and i understand many complex things that are above my age category such as newton's laws and vectors, projectile motions, electronic configurations and orbitals(i know that's chemistry) and i know many more things - but i had an idea, which according to Newton's Laws could work.

According to Newton's 3rd law, if a force from 1 body is exerted onto a 2nd body, the 2nd body will exert a -F, which is equal in magnitude to F, but opposite in direction. So i thought, because light is made of particles and they move very fast, couldn't you propel vehicles on pure radiation instead of having cars? According to newton's law, if light moves away from the vehicle, the vehicle will evert a -F with the same magnitude but opposite in direction. Now, i realise that light's pressure would be very weak - but what if a reflecting surface was involved to double or multiply light's pressure? It's just an idea i had - and i'm 15 so don't go hard on me! But i think it's possible!

2. Sep 22, 2009

### chroot

Staff Emeritus
You can definitely use light (or any radiation) to propel a vehicle. So-called solar sails would be propelled by the radiation pressure from the Sun.

Congrats for figuring that out on your own!

- Warren

3. Sep 22, 2009

### Vincit

i actually thought i was onto something:(

4. Sep 22, 2009

### HallsofIvy

I believe chroot just said you are!

5. Sep 22, 2009

### Vincit

i guess, but i thought the idea wasn't thought of before:D

But now if there's solar sailing(which i didn't know existed) - i guess that mean's SOMEONE had to have thought of that.

6. Sep 22, 2009

### Bob_for_short

The pressure of light was discovered by Lebedev in 1900. In school lab you may find a vacuum bulb with rotating thing when lighted by Sun. http://en.wikipedia.org/wiki/Radiation_pressure. You should be content with you - you made the right reasoning.

7. Sep 22, 2009

### Vincit

i attend a public school, and it's very frustrating. I'm in the top set for science - but i'm far ahead of the class and i already know everything teach us. It's just frustrating and i need some suggestions as to what i can do. I do A Level physics at my house- and i do not find it too complex at all.

8. Sep 22, 2009

### Feldoh

You are, coming up with creative ideas, even if they have all ready been discovered, is still a very very valuable quality to have, IMO.

Perhaps you might want to take some time to read some books on interesting topics in physics. Or perhaps learn calculus and try to self-study the introductory college physics consisting on Newtonian mechanics and e&m

9. Sep 22, 2009

### Staff: Mentor

Don't worry about thinking up wonderful ideas that have already been thought of before. You will keep on doing it even through graduate school!

10. Sep 22, 2009

### Vincit

Someone give me an idea - so i can improve the world when im older! but then it wouldn't be my idea... someone give me a base to start off with!

11. Sep 22, 2009

### chroot

Staff Emeritus
12. Sep 22, 2009

### qsa

I was a hot shot myself when I was in high school (16 years old), I discovered the NON-Newtonian calculus at the same time as R. Katz and M. Green; among many other less important things. You’re absolutely correct, most people (almost all) are too involved in their own lives and they will only look at thing that is relevant to what they are doing directly. Your teachers will keep teaching by repeating themselves like parrots, so don’t expect much from them. Here is what you need to do
1. Go to a university library and scan all the books of the subjects of interest. Out of 20 books on the same subject one or two are usually the best ones, the rest are repetitive and good for verification and to know something that is not mentioned clearly in the others. Try to figure out how the subjects relate to each other, especially mathematic it is a vast subject with overlapping parts.
2. Learn as much as possible computer programming, it is an essential tool of science. And it will sharpen up your brain.
3. Read some engineering books, technology ties theory to practical things. It clarifies their relation and makes both more understandable.
4. Read book on philosophy and its history, philosophy of physics and philosophy of mathematics. Scan through them you do not to know every detail, you can always come back to them as you become more knowledgeable.
5. Go to your book store and buy scientific magazines like Scientific American, Scientists and the like. Buy some layman books on Physics for authors like lee Smolin, Brian Greene, Paul Davis, Roger Penrose, David Deutch , Micho Kaku and many others.( you can google ). Of course, these are only examples there are many others, and yes, for mathematics too.
6. Also scan some business books, they teach you management which will be very useful when you eventually try to create some serious project, well maybe even if it is not so serious.
I really commend you highly for your question, and I have seen many with PHDs who do not ask this question and do not know the answer either. You are welcome to ask me any more questions. You can find my email in my site www.qsa.netne.net.

Good Luck

qsa

13. Sep 22, 2009

### Monocerotis

Vincit may be on his way to becoming the next Terence Tao.

It might just help to read advanced physics and mathematics books in preparation for university; once you start attending courses there the material would already be second nature.

14. Sep 22, 2009

### qsa

1. Go to a university library and scan all the books of subject interest
2. Go to your book store and buy scientific magazines like Scientific American
3. Read books on philosophy and its history, philosophy of physics and philosophy of mathematics

15. Sep 22, 2009

### tony873004

Those are called Crookes Radiometers. But it's only a myth that they rotate from the force of light. http://en.wikipedia.org/wiki/Crookes_radiometer
According to this Wikepedia article we are in good company falling for the myth. Crooke himself, and James Maxwell of Maxwell's equations believed light pressure caused the motion. But it spins the opposite direction that light would make it spin.

16. Sep 22, 2009

### qsa

1. Go to a university library and scan all the books. Out of 20 books on the same subject one or two are usually the best ones, the rest are repetitive and good for verification and to know something that is not mentioned clearly in the others. Try to figure out how the subjects relate to each other, especially mathematic it is a vast subject with overlapping parts.
2. Lear as much as possible computer programming, it is an essential tool of science. And it will sharpen up your brain.
3. Read some engineering books, technology ties theory to practical things. It clarifies their relation and makes both more understandable.
4. Read book on philosophy and its history, philosophy of physics and philosophy of mathematics. Scan through them you do not to know every detail, you can always come back to them as you become more knowledgeable.
5. Go to your book store and buy scientific magazines like Scientific American, Scientists and the like. Buy some layman books on Physics for authors like lee Smolin, Brian Greene, Paul Davis, Roger Penrose, David Deutch , Micho Kaku and many others.( you can google ). Of course, these are only examples there are many others, and yes, for mathematics too.
6. Also scan some business books, they teach you management which will be very useful when you eventually try to create some serious project, well maybe even if it is not so serious.

17. Sep 22, 2009

### vanesch

Staff Emeritus
That's THE problem of having an idea
I've also had many brilliant ideas just to find out that others had had them too :shy:

That leaves you with a double sentiment: one is that you are quite proud of yourself ("hey, I figured this out myself!"), the other that you lost your time ("if only I had looked a bit more in the literature...").

Honestly, when you're pretty young, even if you're bright, it is already very good to have ideas that aren't outright wrong. To have *new* ideas means not only that you are good, but also that you have very good knowledge of the actual state of a field (literature knowledge). In fact, it is almost suspect to have a new idea that hasn't been thought of before. Chances are it is a bad idea (but not always). It is very difficult to have a good idea without anyone else having had it.

Finally, if you're bored stiff in high school on science subjects, that's pretty normal I'd say. Things will change when you're in university. The change in pace is something like going from a sailing boat to a jet fighter. Enjoy the time while you still have some

18. Sep 23, 2009

### Vincit

Thanks for the suggestions and help, everyone. I'll take everything into account.

OT: What if we took Solar Sailing onto land? We would need to mulitply light's strength as light's pressure would be too weak to exert a force of enough magnitude.

19. Sep 24, 2009

### chroot

Staff Emeritus
Yeah, solar sails will only work in vacuum. The wind resistance (air drag) of a large sail would totally negate the very small force due to the radiation.

- Warren

20. Sep 24, 2009

### qsa

even if you enclose the sails in vacuum and store the energy generated you would probably need a sail the size of chicago, that is no way to drive a car. And if you use a powerfull laser to multiply your photons and concentrate them is small area, you know what is going to happen? right