To study the behaviour of classical particles, classical waves, and quantum objects towards the double slit by using the following three physical models:

1. Double-Slit Diffraction (Classical Particles: Sand)

To observe how particles passing through a narrow opening form a spread-out pattern, illustrating the idea of diffraction in a classical context.

2. Double-Slit (Young's) Interference (Classical Wave: Water)

To investigate how water waves passing through two slits interfere to form a pattern of alternating constructive and destructive interference.

3. Quantum Interpretation (Quantum Object: Electron or Photon)

To explore how quantum particles such as electrons or photons exhibit wave–particle duality and reproduce interference patterns—even when fired one at a time.