Types of Waves Longitudinal wave Transverse Wave oscillations are in the direction of motion (parallel to the motion) Transverse Wave oscillations are perpendicular to the direction of Motion

Physical Examples Longitudinal wave Transverse Wave sound waves earthquake P-waves Transverse Wave water waves earthquake S-waves light waves

Wave Parameters Wavelength (l) length or size of one oscillation Amplitude (A) strength of disturbance (intensity) Frequency (f) repetition / how often they occur per second

Wave Properties Waves are oscillations and they transport energy. The energy of a wave is proportional to its frequency. Fast oscillation = high frequency = high energy Slow oscillation = low frequency = low energy The amplitude is a measure of the wave intensity. SOUND: amplitude corresponds to loudness LIGHT: amplitude corresponds to brightness

What is the Wave length? Measure from any identical two successive points (nm) 5 10 15 20 25 30 35 40

What is the Wave length? Measure from any identical two successive points (nm) 5 10 15 20 25 30 35 40 30nm – 10nm = 20nm

What is the Wave length? Measure from any identical two successive points There are 4 complete oscillations depicted here ONE WAVE = 1 COMPLETE OSCILLATION (nm) 5 10 15 20 25 30 35 40 22.5nm - 2.5nm = 20nm

Frequency Frequency = number of WAVES passing a stationary point per second (Hertz)

Doppler Effect Change in frequency of a wave due to relative motion between source and observer. A sound wave frequency change is noticed as a change in pitch.

Constructive Interference Waves combine without any phase difference When they oscillate together (“in phase”)

Wave Addition Amplitude ~ Intensity

Destructive Interference Waves combine differing by multiples of 1/2 wavelength They oscillate “out-of-phase”

Wave Subtraction

BEHAVIORS OF WAVES Standard 8-6.4 Summarize the behaviors of waves (including refraction, reflection, transmission and absorption).

VOCABULARY WORDS: 4 Ways that waves interact 1. Reflection: When a wave hits a surface through which it cannot pass, it bounces back.

2. Refraction: Is the bending of a wave as it moves from one medium into another medium at an angle, it changes speed as it enters the second medium, which causes it to bend.

3. Transmission Occurs when waves pass through a given point or medium. example: Sound waves transmitted thru solids, liquids and gases. Radio waves are transmitted through one electron through another. Light waves are transmitted – 3 ways light and matter can pass through material. A. Transparent material: Only a small amount of light is reflected or absorbed (may be clear or colored material such as filters, windows).

B. Opaque material: allows no light waves to be transmitted through them. C. Translucent materials: Transmit some light, but cause it to be scattered so no clear image is seen.

4. Absorption - Occurs when the energy is not transferred through or reflected by the given medium Disappearance of an electromagnetic wave into a medium. Opposite of reflection We see colors because of the selective absorption of visible light. Objects absorb certain wavelengths and we see what is leftover. The colors we see depend on the wavelength absorbed.

Absorption The apple absorbs all wavelengths except red. Yellow Green Red Blue Red Orange Violet The apple absorbs all wavelengths except red. The apple reflects mostly red. Therefore, it looks like red. Essay question on test!!!

Absorption A material that absorbs all wavelengths of visible light will appear black. In contrast, a material that reflects all wavelengths will appear white. Objects or substances that absorb any wavelength of EM radiation become warmer and convert the absorbed energy to infrared radiation. (GREENHOUSE EFFECT)

1. WHAT ARE THE 4 WAYS WAVES WILL INTERACT? Reflection Refraction Transmission Absorption 2. WHAT ARE THE 3 WAYS LIGHT AND MATTER CAN PASS THROUGH? Transparent Opaque Translucent 3. WHAT IS THE COLOR WHITE AND THE COLOR BLACK? White is all color reflected Black is all color absorbed

Wave video Properties of Waves

WAVE MOVEMENTS AND EM WAVES INTERFERENCE: When two or more waves are moving through a medium at the same time. -The energy of the waves may interact by adding together or canceling out as they pass. (Tsunami waves) - Once the waves have passed each other, they continue unchanged by the interaction. http://physics-animations.com/Physics/English/int_txt.htm

Interference Constructive Interference – When two waves combine to make a wave with larger amplitude. “Helping each other” Destructive Interference – When the amplitude of two waves combine with each other producing a smaller amplitude.

DIFFRACTION: Is the scattering of a wave as it hits the edges of a boundary or tiny opening. The wave will try to curve around the boundary or outward through the opening. A moving object has energy. The moving object can transfer energy to a nearby medium, creating a wave.

EM (Electromagnetic Waves) How do electromagnetic waves differ from mechanical waves? EM waves do NOT need a medium to travel through.

EM Waves Every time you feel the sun’s heat, listen to your MP3 player, or pop a bag of popcorn in the microwave, you are using a different form of the electromagnetic energy. EM waves make these events possible.

EM Waves EM waves are transverse waves that have some electrical properties and some magnetic properties. It consists of changing electric and magnetic fields. EM waves travel as vibrations in electric and magnetic fields.

EM Waves EM waves vary based on wavelength, energy and frequency. Electromagnetic energy is created by vibrations (just like mechanical waves). This produces waves that carry the energy. Each EM wave emits at different energy levels. The collection of all EM frequencies is known as the “Electromagnetic Spectrum”.

Electromagnetic Spectrum

Electromagnetic Spectrum 1. Radio waves are used to transmit radio and television signals. Radio waves have wavelengths that range from less than a centimeter to tens or even hundreds of meters. Longest wavelength, lowest frequency and least amount of energy. They travel long distances by reflecting their signals off Earth’s atmosphere or off satellites.

Electromagnetic Spectrum 2. Microwaves – shorter wavelengths, higher frequencies, and more energy than radio waves. Cell phones and radar are two uses of microwaves. 3. Infrared Light - is the region of the electromagnetic spectrum that extends from the visible region to about one millimeter (in wavelength). Infrared waves include thermal radiation. Associated with heat

Electromagnetic Spectrum 4. Visible Light – The range of EM waves that can be detected by the human eye. Longest wavelength is of visible light is red. Shortest wavelength of visible light is violet. The color we see is determined by the way the light interacts with the object. How it is reflected and how it is transmitted. 400 – 700 nm (nanometers)

Visible Light Each of these colors actually corresponds to a different wavelength of light.

How Roy G. Bv Lost a Vowel The sequence of colors red, orange, yellow, green, blue, and violet may be remembered by memorizing the name of that fine fellow "ROY G. BV". This was originally "ROY G. BIV", because it used to be common to call the region between blue and violet "indigo". In modern usage, indigo is not usually distinguished as a separate color in the visible spectrum; thus Roy no longer has any vowels in his last name.

Electromagnetic Spectrum 5. Ultraviolet Light (UV)- Higher frequency than visible light and carry more energy. Can damage or kill living cells Tan skin by the sun or tanning bed

Electromagnetic Spectrum 6. X-rays - high energy waves which have great penetrating power and are used extensively in medical applications and in inspecting welds. The wavelength range is from about ten billionths of a meter to about 10 trillionths of a meter. Short wavelengths and high frequencies allow them to travel through skin, but not bone (more dense)

Electromagnetic Spectrum 7. Gamma Rays – Shortest waves, with the highest frequency (and highest energy). They are more penetrating than X-rays Can kill living cells Used to sterilize medical equipment

How do prisms separate visible light? When light shines through a prism, the glass changes the behavior of each light wave according to the wave's wavelength. This property of glass is known as its refractive index. The prism changes the direction the light is traveling. As a result, what goes in as ordinary white light comes out separated into a spectrum of different colors. That's because white light is really all those wavelengths mixed together.

Visible Light Each of these colors actually corresponds to a different wavelength of light.

How Roy G. Bv Lost a Vowel The sequence of colors red, orange, yellow, green, blue, and violet may be remembered by memorizing the name of that fine fellow "ROY G. BV". This was originally "ROY G. BIV", because it used to be common to call the region between blue and violet "indigo". In modern usage, indigo is not usually distinguished as a separate color in the visible spectrum; thus Roy no longer has any vowels in his last name.