Simulation Using Electrons

Open the Double Slit program and click on the source tube labeled Electrons on the left side of the screen. Click Start to see what happens. Describe the pattern that accumulates.

In comparison with the other interference patterns you have observed answer the following questions:

• Which pattern(s) - light, waves or particles - does the pattern for electrons resemble?
• What can you conclude about the behavior of electrons in a double slit experiment?

Similar experiments resulted in a conclusion that electrons behave as waves. This result was surprising but inescapable. As we shall see, it is confirmed in many situations.

Let us see how the electron interference pattern changes with the energy of the electron.

Instructions:

1. Keeping other variables fixed try at least four different energies and measure the approximate distance between consecutive dark areas on the screen.
2. You can make approximate measurements using the scale directly above the pattern.
3. You can save and compare your runs by clicking and dragging the pattern over to the spaces provided on the right hand side of the screen.

How does the distance between dark areas change as the energy increases?

Recall how the patterns for photons (or light) changed with wavelength. Let us suppose that an electron has a wavelength related to its energy in the same way as light. Using this information, describe below how the electron's wavelength changes as the energy increases.