# What is the exact definition of a wave?

1. Aug 27, 2008

### granpa

I know it when I see it but what is the exact definition of a wave? what makes a wave a wave?

2. Aug 27, 2008

### kateman

3. Aug 27, 2008

### granpa

you call that exact? thats little better than 'I know it when I see it'.

4. Aug 27, 2008

### jaseh86

The textbook definition is something like "A propagating disturbance that carries energy".

What makes a wave really a wave would be its wave properties.
All waves experience the following under certain conditions:

Reflection, refraction, polarisation, interference and superposition and diffraction.

5. Aug 28, 2008

### Staff: Mentor

To me, a wave is a motion that satisfies the differential wave equation.

6. Aug 28, 2008

### pardesi

here is what i think of waves as

7. Aug 28, 2008

### atyy

Hmm, this won't work for nonlinear waves or the Schroedinger equation.

This doesn't work for standing waves.

Interference is my personal favourite - Young's double slit is so signature! But is it defined when superposition doesn't hold?

So maybe these definitions are still the best?

8. Aug 28, 2008

### jaseh86

A standing wave is still considered a disturbance in space-time right?

How about wave = "a disturbance....in the force"

9. Aug 28, 2008

### Phrak

My personal favorite is a cold snap, the inverse of a heat wave.

Odd that it's so hard to pin down. A string can support reflection if the mass density of the string changes, but as a one dimensional wave, diffraction and refraction are out.

10. Aug 29, 2008

### vanesch

Staff Emeritus
I think the word "wave" is heavily overloaded with meanings, definitions and all that, and it depends on the context what is exactly meant by it. However, within many contexts, an exact definition can be given, and there are some similarities to them over all these classes, which comes down to "stuff that wobbles in space and time".

11. Aug 29, 2008

### granpa

12. Aug 30, 2008

### atyy

13. Aug 30, 2008

### xCross

Wave is a simple harmonic motion which carries energy and information through an object but do not move object's particles..

14. Aug 30, 2008

### Antenna Guy

Within an antenna context, a wave describes the instantaneous energy passing through a closed surface containing the radiator. Usually, the closed surface is defined as a sphere for simplicity (since all points on the surface are equidistant from a single reference point - the phase center).

For extended objects (where the smallest sphere that completely contains the radiator is many wavelengths in diameter), the instantaneous energy distribution on that closed sperical surface can be anything but simple (although it is merely a superposition many simple waves).

Regards,

Bill

15. Aug 30, 2008

### Chaulesh

A wave is a disturbance that carries energy (not matter) from one point to another through a series of continuous movements.

There exists two types of waves : transverse and longitudinal waves.

The difference between the two is the way they carry the energy from one point to another.

A transverse wave transfers energy through series of upwards and downwards oscillations.

A longitudinal wave transfers energy through a series of compressions and rarefactions (expansions).

Some waves are a combination of both like water waves.

A good site to visit for clearer explanations on waves is:

http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html

16. Aug 31, 2008

### Antenna Guy

Spherical waves have both tangential and radial components, but the radial component tends toward zero as the radius increases beyond $\frac{2 D^2}{\lambda}$.

Regards,

Bill

17. Sep 5, 2008

### richa0239

A wave is a disturbance that propagates through space and time, usually with transference of energy. Waves travel and transfer energy from one point to another, often with little or no permanent displacement of the particles of the medium instead there are oscillations around almost fixed locations.
Wave is
-A movement like that of a sudden occurrence or increase in a specified phenomenon.
-One of a series of ridges that moves across the surface of a liquid .

Examples of waves are:

Ocean surface waves, which are perturbations that propagate through water.
Sound — a mechanical wave that propagates through air, liquid or solids.
--------------
Richa

18. Sep 14, 2008

### skydancer46

A wave is not quite a thing (mass), but more than a thought (C squared)

Last edited: Sep 14, 2008
19. Sep 14, 2008

### skydancer46

A wave is not quite a thing (mass), but more than a thought (C squared)