This is a detailed lesson plan and powerpoint that covers the topic of Double (or Twin) slit interference
Path difference. Coherence.
Interference and diffraction using a laser as a source of monochromatic light.
Young’s double slit experiment: the use of two coherent sources or the use of a single source with double slits to produce and interference pattern.
Fringe spacing formula
Students are expected to show awareness of safety issues associated with using lasers.