I. What is a Wave?  A. A wave is a repeating disturbance or movement that transfers energy through matter or space. 1. The matter in which a wave travels is called a medium & it can be a solid, liquid or gas.

II. Waves  A. There are 2 main types of waves: 1. Mechanical – travels through matter only ○ Ex. Transverse vs. Compressional 2. Electromagnetic – travels through matter & space  B. Travel at the speed of light 3.0 x 10^8 m/s

 Transverse Matter in the medium moves at right angles to the direction that the energy travels ○ Ex. Ocean Wave  Compressional Medium moves along same direction that the energy in the wave travels ○ Ex. Sound Wave

Both Transverse & Compressional

III. Properties of a Wave (Review)  A. All waves share these common characteristics: 1. crest – high point of a wave 2. trough - low point of a wave 3. rarefactions – less-dense regions of a compressional wave 4. Constructive vs. Destructive Interference

III. Properties of a Wave (Review)  B. All waves have: 1. Wavelength: distance from one crest to the next crest 2. Frequency: how many (wavelengths) cycles pass at one point in one second (to increase the frequency, decrease the wavelength) ○ a. The amount of energy transferred depends on the waves frequency: higher frequency higher amount of energy transferred 3. Period – time it takes for a wavelength to pass a point 4. Amplitude: distance between the highest point to the lowest point on a wave

III. Properties of a Wave  C. Waves travel at different speeds depending on a few factors Type of wave Medium it is traveling in Temperature of medium  D. To calculate a waves speed Speed = frequency x wavelength

IV. What is an EM Wave?  A. Transport radiant energy from one place to another without transferring matter 1. They are produced by charged particles that are in motion & collide with one another  B. Force fields composed of a magnetic & electric part allow these waves to exert forces between objects that are not touching

V. Electromagnetic Spectrum  A. The range of all of the electromagnetic radiation frequencies is called the Electromagnetic Spectrum 1. Light travels slower the thicker the substance it has to go through (faster in a gas then in a liquid or solid)

VI. Waves of the Electromagnetic spectrum  1. Radio waves-the longest wavelengths Used to transmit radio and TV signals and Radar detectors  2. Microwaves- shorter radio waves Used to transmit phone calls in portable and cellular phones as well as used in microwave cooking  3. Infrared Waves- Feeling the warmth off a fire you are feeling the infrared waves from the fire Used in night vision, snakes use infrared waves to detect their prey

VI. Waves of the Electromagnetic spectrum  4. Visible Light waves-waves you can detect with your eyes Electrons gaining energy vibrate, if they vibrate so much the temp increases and might glow All the colors you see are just at different wavelengths of the visible light spectrum Red is the longest & violet is the shortest wavelength  5. Ultraviolet -emitted by the sun and reaches earth’s surface A lot can be enough to damage or kill living cells, example sunburn Uses-sterilization, make vitamin D, ozone is absorbed by the earth’s ozone to protect earth from UV, gamma, x-ray

VI. Waves of the Electromagnetic spectrum  6. X-ray- can go through your skin and muscles Uses-to find broken bones  7. Gamma- highest frequency, most energy Dangerous with exposure they can help with cancerous cells