# The Principles of Heat, Light, and Sound Heat The movement of heat is from… Hot Cold.

## Presentation on theme: "The Principles of Heat, Light, and Sound Heat The movement of heat is from… Hot Cold."— Presentation transcript:

The Principles of Heat, Light, and Sound

Heat

The movement of heat is from… Hot Cold

Heat is transferred three ways… Conduction Convection Radiation

The first form of heat transfer is… Conduction

Conduction is heat transferred by contact. Source: Maybryonline.org

Examples… Mr. Hand's 8 th Grade Science Site University of Virginia Physics Department

What stops heat transfer? An Insulator.

Examples…

The second form of heat transfer is… Convection

Hot rises, cold falls creating currents. “Older Than Dirt” WebQuest Think Energy (UK)

Examples of convection

The third form of heat transfer is… Radiation

Radiation is heat as an electromagnetic wave.

The wave becomes heat when it hits an object.

Light

Sources of light…

A light source produces light.

What happens when light hits an object? The light is reflected off the object.

We see things because of reflected light. We see red, because red light is reflected; blue because blue is reflected; white because all light is reflected.

We see ourselves in a mirror because of reflection.

The light that hits an object is called the angle of incidence. The light that bounces off the object is called the angle of reflection.

Angle of incidence = Angle of reflection Molecular Expressions

When light passes thru transparent objects (water, glass, etc.), the light is refracted (bent).

When light passes thru water, it’s refracted. http://www.nature.com

When light travels thru a prism, the refraction forms the spectrum. DiscoveryEducation Clipart

The spectrum is the colors of the rainbow…

Red, Orange, Yellow, Green, Blue, Indigo, and Violet (ROY G. BIV).

Three things can happen when light hits an object.

If the object is transparent, it will pass through it.

If the object is translucent, light is diffused as it passes through it. Designbuild-Network.com

If the object is opaque, the light will not pass thru the object and is reflected.

Sound

Sound is caused by vibrations.

Sound moves out in every direction.

To have sound, you must have a medium.

If there is no medium, there is no sound.

A property of sound is pitch. Pitch is how high or low a sound is.

How much energy is used determines the volume (how loud) of the sound.

A lot of energy – a loud sound.

A little energy – a soft sound.

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