Light and Color

Electromagnetic Spectrum

Tour the electromagnetic spectrum

http://www.pbs.org/wgbh/nova/physics/electromagnetic-spectrum.html

http://missionscience.nasa.gov/ems/01_intro.html

What is the speed of an electromagnetic wave?

All waves travel at the speed of light

3 x 108 m/s

How does this compare to sound

Light travels faster than soundFor example fireworks and lightning

Does anything affect the speed?

Traveling though different mediums affect speed. In what medium below does speed go the fastest and slowest? A. AirB. VacuumC. Water

Speed of light through mediums

Through a vacuum like space?

Speed of light through medium

Through air?

Speed of light through medium

Through water?

Why does this happen?

Visible light

How do we remember colors?

RoyGBiv video:http://vimeo.com/5377784

Why is the sky blue?

Higher frequency light is scattered more easily. The purple end of the visible light reflects off particles in the atmosphere and appear to our eyes.

Speed

C = λ fwhere c = 3 x 108 m/s

C is the same for all EM waves

Because c is the same, the relationship of λ and f are inversely proportional.As λ goes up f goes down and vice versa

What type of wave is a light wave?

Light is an electromagnetic wave and transverse.It is a combination of electric and magnetic fields.

Polarized Light

Why do you wear polarized sun glasses?

Polarized lens

Demo of lenses

Light transmission through lens

Only some light is transmitted through a polarized lens.

Transmission-light passing through a medium

When light shines on surfaces

• Transmission-passing through of light• Reflection-light bouncing off• Absorption-light not reflecting or transmitting

Light on surfaces

Why do we see color?

Color or visible light is the light that is reflected. The color you see is the reflected light, all other colors are absorbed.

Which surface is cooler on a sunny day?

Temperature of surfaces

Darker surfaces absorb light and collect their energy and become warm.Light that is transmitted through does not get absorbed and feels cooler.

Light is a wave and particle

Why is light a particle? What are the particles in a light wave?

Why is light a wave? What characteristics make it behave like a wave?

Double Slit Experiment

Wave characteristics:http://www.falstad.com/ripple/Simulation experiment double slit:http://en.wikipedia.org/wiki/Double-slit_experimentMIT student doing double slit:http://video.mit.edu/watch/thomas-youngs-double-slit-experiment-8432/Dr. Quantum double slit experiment:http://www.teachertube.com/viewVideo.php?video_id=50333Or Ted talks:http://ed.ted.com/on/dCXpSQhi