1. 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.

2. 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.

3. Transverse
Longitudinal

4. Longitudinal Wave
Compression- Parts of the wave that are close together.
Rarefaction- Parts of the wave that are spread apart.

5. Transverse Wave
Rest Position- particle position before being disturbed.
Crest- high point
Trough- Low point
Wavelength- Distance from one particular point to the next (crest to crest)
Amplitude- maximum distance medium moves from rest position.

6. 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).

7. The Speed of Sound is affected by:
Elasticity
Density
Temperature

8. 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.

9. Temperature
Sound travels slower in lower temperatures than higher temperatures.
Density
When comparing two solids with different densities sound will travel slower in the denser solid.

10. Interactions of Waves
Reflection- Wave Bounces back when it hits surface. A reflected sound is an echo.
Diffraction- Waves bend around corners

11. 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.

12. Human Ear

14. Vocabulary Transmits- Allows the light through.
Absorbs- Takes the light in.
Reflects- The light bounces back.

15. 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

17. Vocabulary Prism- Glass triangle used to disperse or refract light.
Filter-Transmits only its own color.

18. 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.

19. Black- absorbs all colors
White- reflects all colors

20. 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

21. Pigments
Pigments 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.

22. The angle of incidence always equals the angle of reflection

23. 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.

24. Two Types of Image Virtual- Upright
Real- Upside down. May be larger or smaller than the object. Rays of light meet. (Focal Point)
Virtual- Upright

25. Types of mirrors Plane- Flat, makes a virtual image
Convex- Curves outward, makes virtual image.
Concave- Curves inward, makes virtual and real.

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

27. Two Types of Lenses
Convex- Thicker at the center. Makes real or virtual images.
Concave- Thinner at the center. Makes virtual images.

28. The Human Eye

29. Correc