Essential Understandings:
● basic characteristics of visible light
● the colors of the visible spectrum
● terms opaque, transparent, and translucent
● prism effect on white light 
● the relationship between refraction of light and rainbows
● the parts of compression and transverse waves
● why sound waves travel only where there is matter
● the relationship between frequency and pitch
● the relationship between wavelength and the color of light
● what factors affect the pitch of a vibrating object
​● the uses and applications of sound waves
Essential Skills:
● diagramming and labeling a representation of a light wave
● using mirrors to understand the reflection of light
● comparing and contrasting reflection and refraction
● creating and interpreting a model or diagram of a compression wave
● describe what sound is and how it is formed, affects matter, and travels
● comparing and contrasting sound traveling through a solid vs. through air
● comparing and contrasting human sound and hearing with those of animals
​● comparing and contrasting how musical instruments make sound

Light
Light is a form of energy that travels in waves and can move through empty space where there is no air. To be seen light needs to be reflected off a surface.

Transverse Wave
Light waves move in a straight path or a ray.  Light is a transverse wave.  Transverse waves are measured by crests and troughs.  Crests are the highest point of the wave and troughs are the lowest point.

Wavelength

Crest

Trough
A wavelength is the distance between the middle of a crest tot he middle of the next crest.

Ray or Beam
Each of the lines in which light (and heat) may seem to stream from the sun or any luminous body, or pass through a small opening

Reflection
Polished metal surfaces reflect light much like the silver layer on the back side of glass mirrors. A beam of light on the metal surface is reflected.  Reflection involves two rays - an incoming or incident ray and an outgoing or reflected ray.

Refraction
is the bending of a wave when it enters a medium where its speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the normal to the boundary between the two media.

Spectrum
The specturum of light is HUGE!  What humans can see is very small.  We can only see the VISIBLE SPECTRUM.  ROY G BV

Red, Orange, Yellow, Green, Blue,Violet

Remember: the longer wavelength is red -- the long outside of the rainbow.
Violet is shorter - the inside color is shorter in the rainbow.
Transparent
A medium that light travels easily through.
Translucent
A medium that allows scattered light to pass through
Opaque
A medium that does not allow light to pass through

Sound

Sound
Sound is a form of energy produced and transmitted by vibrating matter. 

Vibration
A vibration is a rapid back and forth movement that produces sound. 

Matter
All matter is made of molecules.  Sound travels best through solids because the molecules are more tightly packed together.

Molecule
 A molecule is a group of two or more atoms that are bonded together

Compression Wave
Sound is a compression wave moving outward from its source in all directions.

Compression "Wavelength"
This is a sound wave. A compression is the part of the wave when the molecules are bunched together.

Frequency and Pitch

Frequency
The frequency is the number of waves that move past a point in a certain amount of time.

Pitch
Pitch is the perception of a sound as high or low. A sound’s pitch is a result of the sound wave’s frequency.
Picture
Many tight waves close together  is high pitch.  Spread out waves are low frequency.

High pitch, sounds like a squeaky mouse.

Low pitch, sounds like a thunderstorm

Amplitude
Amplitude is the amount of energy in a compression wave.  High amplitude will make a tall wave on the T chart.  Low amplitude will make a short wave on the t-chart.  Amplitude is VOLUME.  (QUIET or LOUD)

echo
Echoes are the result of sound waves that have hit a solid surface and bounced off (reflected).