TAMU PHYS 221 - PH221_Class22_DoubleSlitDiffractionActivityPlan

Unformatted text preview:

PH221_Class22_DoubleSlitDiffractionActivityPlanPH221_Class22_DoubleSlitDiffractionMaterialsCreated by Tracy J. Rossi / Educational Consultant / F2007 Physics Experiment & Activity Planning Exp/Act: __________________ Course: _______________ Focus: ________________________ Date: ____________ Objectives 1. 2. 3. 4. 5. Core Concepts Physics Mathematical Supplies/Procedures Materials Activity Set-Up Procedures Class 22PH221Double Slit Diffraction11/8/07Observe the Wave Nature of LightRevisit Superposition--Constructive & Destructive InterferenceDerive conditions for Constructive & Destructive Interference from Geometric ApproachDetermine the Wavelength of Monochromatic Source based upon the Interference Pattern* Due to the wave nature of light, interference patterns form when incident through a double slit. * Superposition/Constructive vs. Destructive Interference* laser source * double-slit of known dimensions * rulers * large white boards for screens (optional depending upon the room) * tape measurer or other means of determining the distance from screen to double-slit * large & small white boards * dry erase markersCreated by Tracy J. Rossi / Educational Consultant / F2007 Experiment Activity / Time: ________ Procedures Notes ~ 60 min.The handout, "Young's Double-Slit Activity" (included in binder), asks students to make some predictions and give some explanations w/r.t. the interference patterns before taking data/measurements. They are also asked to create a picture, based on the geometry of the setup, that will help in calculating the wavelength of the source. After small groups complete their initial setup, predictions, etc., groups will create an interference pattern some 10-15 meters from the double-slit and measure the spacing from the centers of the bright and dark fringes. Then, using these measurements, slit spacing, and the geometry developed, students calculated the wavelength of the source.Since we only had one good source (a laser pointer w/ a decent intensity), student groups took turns using the apparatus. since we did not have a stable clamp or setup for the source and slits, and in order to save time, each group did not take "live" measurements at the screen. Instead, they used their dry erase markers to outline the bright fringes on their whiteboards (screens) and took measurements of their marks back at their tables. We used a 532 nm laser pointer, and most groups determined the wavelength to be w/in 20-30 nm of the known value.Created by Tracy J. Rossi / Educational Consultant / F2007 Activity Review / Time: ________ Discoveries Core Concepts Connection to Real-World / Time: ________ Real-World Examples Core Concepts Homework / Review for Next Class Material Covered Text Ref. ~ 15 min.We spent the last 10-15 minutes of class wrapping-up this activity--going over the geometry, determining the conditions for integer bands of constructive and destructive interference, and discussing the wave nature of light. Then, upon solidifying the wave nature of light, we introduced the particle nature of light, starting from the same example, only considering a source so weak that it emits only one photon at a time. Over a long period of time, the weak source would create a distribution pattern, or histogram, matching the interference pattern observed in class.Particle-Wave DualityWhere we discussed the Particle-Wave Duality of light, we also discussed this phenomena for all particles a the Quantum Level, using electrons as a specific example.Particle-Wave DualityCreated by Tracy J. Rossi / Educational Consultant / F2007 Lesson Reflections This activity went exceptionally well, where the students worked well in groups answering questions and setting up the activity on their worksheets ahead of time, taking their measurements, and calculating their results at the end. Most groups were within 20-30 nm of the 532 nm source we used, a few were even w/in 3 or 5 nm. The longest parts of the activity were the initial set-up the students were asked to give, and then cycling groups through using the apparatus in turns. If we had more sources and more sets of slits, this may have taken 10 minutes or so off of the overall activity time used, but most groups completed their initial setups staggered enough not to be trying to use the equipment all at once, at least until the last 3 groups or so. the rationale behind this activity was that it would be better to have the students actually observe the interference patterns and go through deriving the conditions for constructive and destructive interference from the start, instead of "taking it on faith" from a lecture. This then forged a natural path into a discussion of Particle-Wave Duality and Quantum Mechanics--since this course is the direct predecessor of the Modern Physics course, followed by upper-division physics, it was our goal to use this course to help prepare students for some of these higher level concepts ahead of time. The students were engaged in the ending class discussion, where we addressed these issues, and the activity seemed to serve as good preparation for this, as


View Full Document

TAMU PHYS 221 - PH221_Class22_DoubleSlitDiffractionActivityPlan

Download PH221_Class22_DoubleSlitDiffractionActivityPlan
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view PH221_Class22_DoubleSlitDiffractionActivityPlan and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view PH221_Class22_DoubleSlitDiffractionActivityPlan 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?