Basic Idea:

• Three experiments are performed that demonstrate diffraction and interference.

• 1 of each experiment.

	What:	How Many:	Where:
Note: This Experiment is set up in the Phys104 lab, and was hopefully performed the previous week. The only change needed is that the three optical benches with green lasers are removed.
Single & Double Slit Diffraction & Interference:
	Pasco Optical Bench	4	Majors storeroom, shelf P4
	Pasco Optical Bench Screen	4	Majors storeroom, shelf N
	Pasco 650 nm Red Diode Laser & power brick	4	Majors storeroom, shelf N
	Aperture wheel	2 - single slit 2 - multiple slit	Majors storeroom, shelf N
	Sticky notes: "single slit" & "double slit"	2 each	Inside box holding aperture wheels
Wavelength of Red & Green Lasers:
	Pasco Optical Bench	6	Majors storeroom, shelf P4
	Pasco Optical Bench Screen	6	Majors storeroom, shelf N
	Pasco 650 nm Red Diode Laser & power brick	3	Majors storeroom, shelf N
	Aperture wheel	3 - multiple slit	Majors storeroom, shelf N
	Flashlights	1 or 2	Ask Jeff
Limits of Vision:
	2×2 diffraction gratings (slides)	6	non-Majors storeroom, shelf KK4
	2m Metersticks	6	non-Majors storeroom, shelf AA1 & AA2
	Meterstick calipers	3	non-Majors storeroom, shelf AA3
	Blue Variac	1	non-Majors storeroom, shelf L6
	Blue metal stool	1	In the lab or stockroom
Note that the following three items for "Limits of Vision" are already in place on the wall, and should be left there when lab is cleaned up:
	Incandescent display bulb (Type T - tubular, 40W)	1	non-Majors storeroom, shelf M2
	Bulb socket on-a-stick	1	Majors storeroom, shelf N4
	Right-angle clamp	1	non-Majors storeroom, shelf B3
Miscellaneous:
	Flashlights	All Available	Ask Jeff
	Blue Variac	1	non-Majors storeroom, shelf L6

Notes:

• Map of the lab (showing where each experiment will be located):
  • Note that links for detailed photos are with each experiment below

  

   

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Single & Double Slit Diffraction Setup (Phys104 Photo Details):

• Top View:
• Place 4 optical benches on left front bench, in pairs as shown. Optical bench on the left will have the single-slit aperture wheel; the right will have the multiple-slit wheel (used for double-slit)
  • Print two copies of Disc Rotation Directions, and place one sheet on each pair of optical benches near the aperture wheels
  • A sticky note ("single-slit" or "double-slit") is placed on each screen. See photo details
• Use "Variable Slit" for single aperture; "Variable Double Slit" for double. Check alignment of laser; pattern should be near middle of the screen
• Place laser so its base is flush with the end of the track; the pointer of the aperature wheel is at 5 cm mark of optical bench; screen base is flush with end of track
• (Jeff will deal with this): Tape the laser power cord to the underside of the lab bench; gets it out of the way of students writing



 

Wavelength of Red & Green Lasers Setup (Phys104 Photo Details):

• Top view:
  • Remove the three optical benches holding green lasers that were used by Phys104, leaving the three optical benches holding red lasers (Figure A). A multiple-slit wheel is used on each, set to the 4-slit position.
  • Set the pointer of the aperature wheel holder at the 3.5 cm mark for both lasers (Figure B), and set the front edge of the screen at the 112.0 cm mark. (Note that this is closer than the position used by Phys104, since the green lasers have a very large heat sink)
  • Check alignment of lasers so that the pattern is in the center of the screen (Figure C).
  • (Jeff will deal with this): Tape the laser power cord to the underside of the lab bench; gets it out of the way of students writing

Figure A: Green lasers removed from benches after 104 lab

Figure B: Align pointer on grating holder with 3.5 cm mark (arrow)

Figure C: The interference pattern of the red laser

Limits of Vision Setup (Phys104 Photo Details):

• Top view:
  • Place three 2-m metersticks on the floor! The meterstick placement should not begin at the wall, but directly below the bulb. Use a plumb bob to mark this position.
  • (Jeff will deal with this) Secure these 2-m metersticks to the floor with masking tape spaced every 0.5m. It's helpful to write the distance on the masking tape.
  • Place two extra 2-m metersticks on the nearest lab bench. Students will use these "staffs" to measure their position.
  • See the front view below for detail on attaching meterstick to the wall.
  • (Jeff will deal with this) Print five copies of this sign warning people about the meter sticks on the floor; tape to back walls above meter sticks and the ends of the table for the back two benches (especially if you have people who sit here).

  

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• Front view:
  • Secure the meterstick to the wall as shown in detail #1 below (the left side of the meterstick simply rests on the left-hand bolt).
  • The caliper is set at the 0.5 m mark, and the bulb filament at the 1.5 m mark (see detail #2 below); therefore, the caliper marks a distance of 1.0 m from the bulb

  
  (Yes, these are old drawings I made in 2004!)

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• Limits of vision setup detail #1: attaching 2-m meterstick to the wall. Sandwich the right bolt between two calipers; the meterstick simply rests on the left bolt. This holds the meter stick in place. Align so that 1.5 m mark is directly behind the bulb filament (see detail #2 below):

  

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• Limits of vision setup detail #2: attaching bulb to wall. Use a right-angle clamp to secure bulb socket to right side bolt: