Objective:
– To show that laser light hitting a double slit creates a pattern due to a combination of diffraction and interference.
Apparatus:
- Red laser pointer
- “multiple slits (2)” slide from box of grating slides
Method:
Point the red laser pointer at the slits in the middle of the “multiple slit (2)” slide. Project the laser light that passes through the slits onto a wall, screen, or a piece of paper. Observe that there are regular dark bands in the light, along with a broader overall light-dark pattern due to diffraction.
Notes:
You can show just the existence of a pattern with just a handheld grating slide, but this doesn’t enable exploring that pattern or what causes it. To extend the usefulness of the demo, use the “Lasers and Slits” version of the demo.