Waves- Vocabulary

• Wave- disturbance that transfers energy from place to place.

• Medium- material through which the wave travels.

• Vibration (oscillation)- repeated back and forth or up and down movement.

• Mechanical Wave- produced when energy causes a medium to vibrate.

Mechanical Waves

• Transverse- move at right angles to the direction of the energy transfer.

• Longitudinal wave-move parallel to the direction in which the waves are traveling.

• Transverse

• Longitudinal

Longitudinal Wave

• Compression- Parts of the wave that are close together.

• Rarefaction- Parts of the wave that are spread apart.

Transverse Wave

1) Rest Position- particle position before being disturbed.

2) Crest- high point

3) Trough- Low point

4) Wavelength- Distance from one particular point to the next (crest to crest)

5) Amplitude- maximum distance medium moves from rest position.

Sound

• Sound is a vibration that travels through a medium as a longitudinal wave (with compressions and rarefactions).

• You hear the sound when the vibration reaches your ears.

• Sound cannot travel through a vacuum (space with no matter).

The Speed of Sound is affected by:

• Elasticity

• Density

• Temperature

Elasticity• Is the ability of a material to bounce back after

being disturbed.• The more elastic a medium, the faster sound

travels.• Solids are more elastic than liquids.• Liquids are more elastic than gases.

Density

When comparing two solids with different densities sound will travel slower in the denser solid.

Temperature

Sound travels slower in lower temperatures than higher temperatures.

Interactions of Waves

Reflection- Wave Bounces back when it hits surface. A reflected sound is an echo.

Diffraction- Waves bend around corners

Interactions of waves

Refraction- waves bend when they enter a different medium.

Interference- Waves can ‘help’ or ‘take away from each other when they meet.

Human Ear

Vocabulary

• Transmits- Allows the light through.

• Absorbs- Takes the light in.

• Reflects- The light bounces back.

Vocabulary• Luminous- Object that emits light. Ex.

Light bulb• Illuminated- Object that reflects light. Ex.

Anything you see because the light is on.• Opaque- Reflects or absorbs all the light

that strikes it. Ex. The desk.• Transparent-Transmits light. Ex. Clear

glass.• Translucent- Scatters light as it passes

through it. Ex. Wax paper

Vocabulary

• Prism- Glass triangle used to disperse or refract light.

• Filter-Transmits only its own color.

How do we see color?

We see the color that is reflected off the object. For example the leaf is green

because green is reflected.

Black- absorbs all colors

White- reflects all colors

Primary Colors of Light

• Three colors that combine to make any other color. When combined in equal amounts they make white.

• The primary colors are red, blue and green

PigmentsPigments are colored

substances that are used to color other materials. When combined in equal amounts they make black.

The primary colors of pigments are yellow, magenta and cyan.

ReflectionThe angle of incidence always equals the angle of

reflection

Two types of reflection• Regular Reflection-

Occurs when parallel rays of light hit a smooth surface. You see a sharp (clear) reflection.

• Diffuse Reflection- Occurs when parallel rays of light hit a bumpy surface. You don’t see a clear reflection.

Two Types of ImageReal- Upside down.

May be larger or smaller than the object. Rays of light meet. (Focal Point)

Virtual- Upright

Types of mirrors

1) Plane- Flat, makes a virtual image

2) Convex- Curves outward, makes virtual image.

3) Concave- Curves inward, makes virtual and real.

Lenses

Refraction- The bending of light as it enters a new medium as a result of a change in speed.

Two Types of Lenses

• Convex- Thicker at the center. Makes real or virtual images.

• Concave- Thinner at the center. Makes virtual images.

The Human Eye

Correc