"Is it progress if a cannibal uses a knife and fork ?"
Stanislaw Lec

• A particle exhibiting wave-like properties must have a characteristic wavelength, .  The wavelength of a particle, called the deBroglie wavelength, is given by
  
  
  In other words the wavelength is inversely proportional to the momentum of the particle.


• Examples of wave properties we could expect a particle to exhibit are the phenomena of interference and diffraction.  Interference has been mentioned briefly during our discussion of standing waves .


• Due to the small value of Planck's constant (h), wave properties of particles are not seen in our daily lives.  However, one almost familiar example is the electron microscope the operation of which relies on utilising the wave properties of electrons.
  

     Particles can exhibit both particle and wave properties    

• Particle properties dominate at large momentum (small wavelength) e.g. baseballs, grains of sand etc.

• Wave properties become apparent at small momentum (larger wavelength) e.g. elementary particles.


• Theoretically, for any particle it is possible to observe both aspects - but not simultaneously.
  

   Supplementary Problems 

Why did the chicken cross the road ?
Isaac Newton: "Chickens at rest tend to stay at rest, chickens in motion tend to cross roads."