Nicole Ozdowski Samantha Candalor Andrew Lingenfelter Fernando Marill-Tabares

Wave Theory of Light

Aristotle (384 –322 BC) [4th century BC] Pythagoras (570-495 BC) [6th century BC]

17th Century:

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

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

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

Quantum Mechanics: Wave-Particle Duality

Interference

Constructive Interference Destructive Interference

Young’s Double Slit Experiment

Δx = λD/a

Δx r Δx g

= 0.47cm

= 0.40cm

Setting Up the Experiment

Light Sensor and Single Slit Laser and Double Slit

Results

Δx r,th Δx r,exp

= 0.47cm

= 0.467cm

%error = 0.64%

Δx g,th Δx g,exp

= 0.40cm

= 0.413cm

%error = 3.25% Conclusion: Light acts as a wave.

The Photoelectric Experiment

The Concept

Setting Up the Experiment

Mercury Lamp and Detector Meters Amplifier and

Results

● V=(h/e)*f ● Slope is equal to h/e ● h/e = -4.136*10 -15 Js/C ● Our slope = -2.317*10 15 Js/C The closeness of the two values confirms the photoelectric effect.

Conclusion: Light acts as a particle.

Single Photon Detection Double 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 tube Photomultiplier

Results

Theoretical ΔX: 0.2626 cm Experimental ΔX: 0.2622 cm Counts of Single Photons produce an Interference Pattern.

Error: 0.15% Conclusion: Light acts as a wave and a particle.

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 Director Patrick Diggins and Zach McDargh - Project Leaders Patty Yoritomo - Project TA Corporate and Private Sponsors PGSS Alumni Association PGSS Campaign

References

http://en.wikipedia.org/wiki/Thomas_Young_(scientist)#mediaviewer/File:Thomas_Young_(scientist).jpg

http://www.physicsoftheuniverse.com/images/quantum_double_slit.jpg

http://i.stack.imgur.com/Q4brH.gif

http://upload.wikimedia.org/wikipedia/commons/3/39/GodfreyKneller-IsaacNewton-1689.jpg

http://images.gizmag.com/hero/so-you-think-youre-confused-about-quantum-mechanics-9.jpg

http://www.scenicreflections.com/files/Marble_columns_Wallpaper_f3cq8.jpg

http://evlocker.files.wordpress.com/2012/10/2012-02-18.jpg

http://www.marius-riether.com/wp-content/uploads/2013/05/Particles1.jpg

http://www.quantumdiaries.org/wp-content/uploads/2011/07/feynman_qqGamee1.png

https://wiki.brown.edu/confluence/download/attachments/72637259/image003.Png

http://abyss.uoregon.edu/~js/21st_century_science/lectures/lec13.html

http://hdw.eweb4.com/wallpapers/8080/ http://www.faqs.org/docs/qp/chap03.html

http://en.wikipedia.org/wiki/Heinrich_Hertz