Basic Idea:

• Three experiments are performed that demonstrate diffraction and interference.

• 1 of each experiment.

	What:	How Many:	Where:
Note: The optical benches and white screens from last week's Thin Lens experiment are used again this week. Don't put them away!
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
	Pasco 532 nm Green Diode Laser & power brick	3	Majors storeroom, shelf N
	Aperture wheel	6 - 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
	Desk lamps	1	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 (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 (Photo Details):

• Top view:
  • Place 6 optical benches right side benches, in pairs as shown. Optical bench on the left will have the red laser; the right will have the green laser. A multiple-slit wheel is used on each, set to the 4-slit position.
  • Set the pointer aperature wheel holder at the 5.5 cm mark for both lasers, and set the front edge of the screen at the 112.0 cm mark
  • Place benches so that screens are touching (so students can attach one piece of paper to both benches). Check alignment of lasers; so that the red pattern is higher on the screen than the green pattern
  • (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

  

Limits of Vision Setup (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, this is an old drawing 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: