Models

Used for the usefulness of things we cannot see, and is ever-changing

For example..the model of the atom, our current model of light, the elegibunnybutterduck

The Nature of Light

The History of the Nature of Light

How would light act if it were a particle, if it were a wave ?

Light Is a Particle! (Sir Isaac Newton)

Newton thought that light was a particle because the edges of the shadows it created was extremely sharp and clear.

Light Is a Wave! ( Christian Huygens)

About the same time as Newton, Dutch physicist, Christian Huygens, believed that light was made up of waves vibrating up and down perpendicular to the direction of the light travels. It explained diffraction and could be demonstrated through experimentation.

Light Is Also a Particle! (Einstein)

The theory of light being a particle completely vanished until the end of the 19th century when Albert Einstein revived it.

Einstein believed light is a particle (photon) .

Scientists have combined both theorys

The Dual Nature of light is the accepted and current concept of the nature of light.

The Dual Nature of Light

Light is a form of energy.

Sometimes it behaves like a particle and sometimes it behaves like a wave .

For this reason, light is said to have a dual nature

The properties of light can be summarized into two groups…with its dual nature

3 "particle" properties

1) Travels in straight lines2) Reflection (changes direction)3) Refraction (bends, in going from one material to another)

and 3 "wave" properties

1) Interference (waves "superpose" and pass right through each other) 2) Diffraction (waves "spill over" the edges of their obstructions) 3) Polarization (eliminating one of light's "fields")

The Dual Nature of Light Particle properties of light

difficult to explain using the wave theory

Wave properties of light

difficult to explain using the particle theory

Where does the Photoelectric Effect fall, proof of particle or wave ?

The various properties of light, which is a type of electromagnetic wave, are due to the behavior of extremely small particles called photons that are invisible to the naked eye.

The Dual Nature of Light

State the three “wave” properties of light

Interference

Diffraction

Polarization

The Dual Nature of Light

State the three “particle” properties of light

1) Travels in straight lines2) Reflection3) Refraction

The Dual Nature of Light

In your own words, define a photon.

A photon is a packet of energy traveling at a speed of 3 x 108 m/s

Each color is a different photon having a different amount of energy.

A photon of red light has the least amount of energy,while a photon of violet light has the greatest amount

of energy.

The Dual Nature of Light

Define light and explain what is meant by the phrase"the dual nature of light“

Light is a form of energy and has a dual nature. This means that light possesses both particle properties

and wave properties.