practice

1. Write something.
2. Write something.
3. Write something.
4. Write something completely different.

conceptual

1. Matter has both particle and wave properties.
   1. Why don't we notice the particle nature of matter in our everyday experience?
   2. What experimental evidence do we have to show that matter is composed of particles (atoms, molecules, ions)?
   3. Why don't we notice the wave nature of matter in our everyday experience?
   4. What experimental evidence do we have to show that elementary particles can behave like waves?
2. Light and other forms of electromagnetic radiation have both particle and wave properties. Answer the following questions. Provide an example of a device, object, phenomena, or situation that can be used to demonstrate each of the two different models of light. Choose examples from common experience. No fancy laboratory experiments or abstract textbook situations.
   1. What evidence do we have that light is a wave?
   2. What evidence do we have that light is composed of particles (photons)?

numerical

1. The Davisson-Germer experiment that first demonstrated the wave nature of mater used electrons accelerated to 54 V.
   1. Determine the energy of the electrons in …
      1. electron volts
      2. joules
   2. How fast were they moving? State the speed in …
      1. m/s
      2. mph
   3. What momentum did they have?
   4. Determine the wavelength of the electrons in the Davisson-Germer experiment.
   5. What form of electromagnetic radiation has the same wavelength as the value you calculated in part d.?