Nicole OzdowskiSamantha CandalorAndrew Lingenfelter

Fernando Marill-Tabares

Wave Theory of Light

Aristotle (384–322 BC)[4th century BC] Pythagoras (570-495 BC)

[6th century BC]

Christiaan Huygens (1629-1695)Isaac Newton (1642-1727)

17th Century:

19th Century:

Thomas Young (1773-1829) Augustin Fresnel (1788-1827)

1861:

James Clerk Maxwell (1831-1879)

● Proved that Electricity and Magnetism were expressions of the same thing.

● Found the equality between an electromagnetic wave and light

Einstein’s Photoelectric Effect

Albert Einstein (1879-1955)Heinrich Hertz (1857-1894)

Quantum Mechanics: Wave-Particle Duality

Interference

Constructive Interference Destructive Interference

Young’s Double Slit Experiment

Δx = λD/a

Δxr = 0.47cmΔxg = 0.40cm

Setting Up the Experiment

Light Sensor and Single Slit

Laser and Double Slit

Results

Δxr,th = 0.47cm

Δxr,exp = 0.467cm

%error = 0.64%

Δxg,th = 0.40cm

Δxg,exp = 0.413cm

%error = 3.25%

Conclusion:Light acts as a wave.

The Photoelectric Experiment

The Concept

Setting Up the Experiment

Mercury Lamp and Detector Amplifier and Meters

Results● V=(h/e)*f

● Slope is equal to h/e

● h/e = -4.136*10-15 Js/C

● Our slope = -2.317*10-

15Js/C

The closeness of the two values confirms the photoelectric effect.

Conclusion: Light acts as a particle.

Single Photon DetectionDouble Slit Experiment

● Repeat the double slit experiment

● Count photons instead of measuring intensity

● If light is a wave then detector

won’t count

● If light is a particle, there won’t be an interference pattern.

Experimental Setup

Laser and Double Slit Photomultiplier tube

Results

Counts of Single Photons produce an Interference Pattern.

Conclusion:Light acts as a wave and a particle.

Theoretical ΔX:0.2626 cm

Experimental ΔX:

0.2622 cm

Error: 0.15%

Conclusion

Is light a wave?The double slit experiment says yes.

Is light a particle?The photoelectric experiment says yes.

Is light both?The photon detection experiment says

yes.Therefore…

Light is a Wavicle.

Quantum Mechanics: Wave-Particle Duality

Light as a Wave:

● Well defined momentum and wavelength

● Position is spread out and unclear

● Can interfere and diffract as a wave would

Light as a Particle:

● Well defined position

● Wavelength is unclear

● Can slam into particles

Acknowledgments

Dr. Luokkala - PGSS DirectorPatrick Diggins and Zach McDargh - Project LeadersPatty Yoritomo - Project TACorporate and Private SponsorsPGSS Alumni AssociationPGSS Campaign

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