2007 The Atom and Quantum Mechanics Name _______________________

Please assign a rating to each activity. 1 = Worthless 10 = Excellent These links are available in the MLC Learning module.

PhET Simulations, Colorado http://www.colorado.edu/physics/phet/web-pages/simulations-base.html

This link is in our MLC Learning module. When the page opens, scroll down the left navigation box and click on Index.

______ 1. Click on the Quantum Wave Interference link. Wait for it to load.

Photons

Try the simulation with both red and green light. You may want to increase the intensity of the light.

Change the gun to emit Electrons by using the control at the bottom left of the window.

Try the electron simulation with two different velocities.

TRUE or FALSE There is more distance between the minima on the screen when the electron velocity is low than when the electron velocity is high.

Optional: Change the slit width and slit separation.

Close the simulation window.

______ 2. Click on Neon Lamp and other Discharge Lamps Link. Click on the Single Atoms tab at the top left if it is not selected. Set the electron production to continuous. Click on the Spectrometer, Squiggles, and Slow Motion checkboxes. What level in the diagram on the simulation does the electron end on when the transition results in the emitted light having a color (e.g. red, green, blue instead of black)? Note that the numbers on the diagram are not the "n" values. The Ground state is n=1 actually.

Click on the Multiple Atoms tab and uncheck the slow motion box. What is the approximate wavelength of the green line? __________

What is the meaning of the numbers that appear and disappear on the atoms inside the tube?

Optional: Try other elements or try a configurable atom. You can drag the energy levels up and down for the configurable atoms. Observe the new wavelengths.

________ 3. Click on the Quantum Tunneling link. Drag the top of the barrier ( purple partial rectangle on the top third of the screen) so the max energy of the barrier is about 0.75 . The energy of the particle (represented by the incoming wave) is 0.5 eV. Thus, the particle has less energy than the energy height of the barrier. The bottom third of the screen shows the Quantum Mechanical probability of finding the particle at a certain location. Restart the simulation. Pause when the time is close to 7.0 fs (femtoseconds).

TRUE or FALSE At this time there is a non-zero probability that the particle is inside the barrier.

TRUE or FALSE There is a non-zero probability that the particle is to the right side of the barrier.

Drag the top of the barrier so the barrier energy is 0.4 eV. Now the particle has more energy than the barrier. Run the simulation until the time is near 7.0 fs.

TRUE or FALSE There is a non-zero probability that the particle is reflected by the barrier.

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