# Light Interference & the Double Slit Experiment Interference & the Double Slit Experiment By Zach Schmidt & Neekaan Oshidary Light: A Particle or Wave

Different tests support different sides of the argument Today: dual theory Young Experiment

Double Slit Analogy Particles Through One Slit Particles Through Both Slits

Interference or Not? The Experiment Components: Light Source: Lasers Double Slit: Pre-made slits Detector: Smooth surface

INTERFERENCE! Testing Variables Distance and Fringe Width

Fringe Width (mm) Fringe Width vs. Distance for Slit Seperations 20 15

0.176 mm 10 0.35 mm 0.7 mm

5 0 1 2 3

4 Distance (m)

w/D=C, DIRECT Where w= fringe width D= distance between slits and detector

C= constant Slit Separation and Fringe Width

w x s=C, INVERSE Where w= fridge width s= slit separation

C= constant Understanding Inverse relation of slit separation and fringe width. Wavelength and Fringe

Width w/C, DIRECT Where

w=fringe width wavelength C= constant Recap of relationships w/D=C,

Distance: direct w*s=C, Slit separation: inverse w/=C, Wavelength: direct Can we combine these into one larger equation?

What about Wavelength? (S S x W)/D Results Helium-neon

laser Our calculation: 610.5 nm Real value: 632.5 Percent Error: 3.5% Particle Nature of Light Light

consists of bundles of energy called photons What would happen if we slowed down the laser, so only one photon at a time arrived at the slits?

Does This Make Any Sense? Conclusion Light behaves like a wave;

interference We used this property to calculate the wavelength of light Light also behaves like a particle This behavior is described in the dual wave/particle theory

THE END!