Developing and Researching PhET simulations for Teaching Quantum MechanicsSam McKagan, Kathy Perkins, Wendy Adams, Michael Dubson, Chris Malley, Sam Reid, Ron LeMaster, Carl

WiemanUniversity of Colorado at Boulder

The Physics Education Technology (PhET) Project is an on-going effort to create a suite of interactive simulations and related education resources that aid in the teaching and learning of physics.•Elaborate Java- and Flash-based simulations•Support for educators and students with resources for both teaching and learning with these simulations•Developed using the results of education research and feedback from educators•Research to formally assess their influence on student learning and attitudes in a variety of settings•A large number of simulations exist and are being used in introductory physics courses around the country•Can be used in lecture demonstrations, recitation activities, or homework assignments•All PhET simulations are free and available at http://phet.colorado.edu

PhET simulations in Quantum Mechanics

The authors thank the Hewlett Foundation, NSF, and the Kavli Operating Institute for providing the support for the PhET Project. We also thank all the members of the PhET Team and the Physics Education Research at Colorado group (PER@C).

PhET Project Overview

Classic Experiments

Teaching with PhET simulationsIn-Class/Lecture Homework

Use the sims as…• a method to promote active thinking with inquiry-based exercises designed

around the simulations. • an alternative to or supplement for traditional introductory physics labs.

Use the sims as…• an effective means of communicating the instructors’ visual

model to the students. • a means for interactive engagement within class using the

Peer Instruction model with simulation-centered concept tests or interactive lecture demos.

• a complementary learning-support tool for classroom demos. • a short pre-class activity to prepare students for class.

INTERACTIONINTERACTIONANIMATIONANIMATION CONTEXTCONTEXT

http://phet.colorado.edu/quantum

VISUALIZATIONVISUALIZATION

Set up a chain reaction

ApplicationsFundamental Principles

“Great sims, I can't imagine QM without them.”

“The simulations were the best part of class, they practically answer physics questions all by themselves. I would recommend continuing to develop these and add more. Without these I think I would have been lost in the course.”

“I definitely not only enjoyed the simulations, but I'd go as far to say that the simulations taught me the most about the course because I could really visualize the inner workings of the physics processes that we going on.”

“I thought the simulations were great. It helped me to gain intuition about the topic. This is especially useful in quantum mechanics where

Student Responses to Quantum Sims

Research on Student Learning with QM sims

Photoelectric EffectPhotoelectric Effect

Quantum Wave InterferenceQuantum Wave Interference

Discharge LampsDischarge Lamps

Lasers:Lasers:

Sample Homework Problems

Sample Concept Test

Acknowledgements

Ranked one of the most useful aspects of the course on end of term survey:

How useful were the following for your learning? (1 – not useful, 2 – a little, 3 –

some, 4 – a fair amount, 5 – a great deal)

posted lecture notes: 4.3the lecture period: 4.2the homework: 4.1the simulations: 4.0posted homework solutions: 3.8studying for exams: 3.7problem solving sessions: 3.5the textbook: 3.2

Nuclear Physics

Photoelectric Effect

Student Responses:

Instructors observed that most students did not know the correct answer initially, but many were able to figure it out through discussion. Graphs that students drew, before seeing multiple choice options, closely matched given options.

it is not normally possible to directly observe the described phenomena.”

“The photon ray gun I first saw in lecture and that was very important to understanding the spread out nature of photons. I used the laser simulation on my own first and had to play with it to get it to lase, which was a good learning experience.”

“This is what really clarified the difference between P and N-type and to figure out what orientation/arrangement is required for a LED to work.”

“I related to this, for my mother has brain cancer. She has MRIs frequently as you could imagine. Now I know what is really going on every time she has one done.”

Davisson Germer: Electron

Diffraction

Lasers

Semiconductors

Conductivity

Watch electron waves tunnel through barriers

See how photon behaves as a wave as it travels through space, and a particle when it hits the screen.

See electrons ejected from plate with varying speeds. Watch them speed up or slow down when voltage is applied.

Visualize not just the interference pattern on the screen, but the

process that creates this pattern.

Find the tumor.

Laser explodes if it builds up too

much power

Visualize phenomena that you can’t observe directly, such as atomic

excitations, electrons, and photons

Configure your atom’s energy levels

View light as photons or waves. Compare and contrast these representations to get a

complete picture

Simplified MRI

See electrons

jump energy levels

Quantum Wave

InterferenceQuantum

Tunneling and Wave Packets

Grab the semi-conductors and put them in the circuit

See electron waves diffract

off atoms

Change the spacing and

radius of atoms

Invite to interact

See time evolution of wave functions

Quantum Bound States

Double Wells and Covalent

BondingBand

Structure

Neon Lights & Other Discharge

Lamps

American Journal of Physics 76, 406 (2008)

Models of the

Hydrogen Atom

Blackbody Spectrum

Stern-Gerlach

ExperimentFourier: Making Waves

All students (N=59)

electrons are waves, explain with interference:

electrons are waves, no explanation:

non-wave explanation:

blank / no explanation:

Students who read (N=38)

36%

29%31%

8%

47%32%

21%

e.g.: ‘You got me. I didn’t read.’

e.g.: ‘The electrons were only detected at certain angles because they were interfering constructively and destructively. It was important because it meant they were acting like waves.’e.g.: ‘The reason for this result of seeing electrons only at certain angles is matter waves. The electrons are traveling with a certain wavelength, making it so they can only be deflected at certain angles.’

e.g.: ‘Shooting electrons at a neatly arranged lattice, the electrons that bounce off will have a higher probability of hitting another atom. Since all the atoms in the lattice are neatly arranged, they will create a series of pathways that the electrons will bounce down. Therefore, the angles they observed were the angles at which the electrons bounced down these “tubes”.’

  a b c NUW w/o Photoelectric Tutor (PT) 40 20 65 26UW w/ PT [see Steinberg et al. AJP 64, 1370 (1996)] 85 40 75 36CU Fa05 (reformed curriculum w/ sim) 87 85 91 189CU Sp06 (reformed curriculum w/ sim) 88 84 86 182CU Fa06 (reformed curriculum w/ sim) 78 77 90 94CU Fa07 (partial implementation of reforms) 72 52 69 65

Would the ammeter read zero current or a non-zero current if you were to:

a. Double the intensity of the light? Why?b. Increase battery voltage? Why?c. Change material of target? Why?

After reading, before lecture w/ sim

After lecture w/ sim 92%

All students (N=74)

Why did Davisson & Germer see electrons deflected only at certain angles?Interactive Lecture - Davisson-Germer: Electron DiffractionInteractive Lecture and Homework

– Photoelectric Effect [accepted to AJP; arXiv:physics:0706:2165]

7%1%

Directly manipulate fourier components and get instant

feedback on how this changes the transform.

See spins deflected through magnets

Fire the photon gun

See the paths of

alpha particles deflected

by nucleus

Rutherford Scattering

Compare the spectra of the sun and a light bulb