6C20.20: Thin Wire Diffraction (strand of hair)
Description: A narrow opaque object will create a diffraction pattern that may be used to measure the width of the object.
The diffraction pattern is like that of a narrow slit, with the width of the object replacing the slit width.
You can try this with a fine wire or strand of your hair.
- Optical bench
- Laser on post
- Magnetic stand and magnetic slide holder
- Either a piece of hair or a thin strand
- Tape measure
- Insert the laser into the optical bench.
- Insert the magnetic stand into the optical bench.
- Ask the professor if he/she wants to use their own hair, or have you pre fit it with a small stand.
- If the professors wants to use their hair, include some masking tape.
- If they want it pre fitted, cut a small thin opaque strand and tape it onto the magnetic slide holder.
- Place the magnetic slide holder onto the magnetic stand and align so the laser will shin on the string.
- Setup in the classroom to allow for the most distance between the laser and screen.
- If using your own hair, take a stand out and tape it onto the stand (see picture).
- Turn on the laser and make sure it's lined up on the thin wire/hair.
- (Optional) Turn off the lights.
- Note the diffraction pattern on the screen is very similar to a single slit diffraction.
- (Optional) Take the appropiate measurments with the tape measure to calculate the width of the thin wire/hair.
- When finished, turn off the laser.
Do not stare into the beam. Keep away from students eyes.