RECOGNIZE WHAT FACTORS AFFECT THE SPEED OF SOUND MEDIUM -rubber slows vibrations, used as soundproofing 2. Temperature -higher the temperature, faster the sound 3. STATES OFMATTER -In gas depends on velocity and mass -travels fastest in solids, then liquids because of orientation of molecules

RELATE LOUDNESS AND PITCH TO PROPERTIES OF SOUND WAVES -greater the amplitude, louder the sound -distance from source - measured in decibels (120 dB deafness) PITCH - How high or low a note sounds - high pitch made by rapid vibrations - low pitch made by slow vibrations -humans hear between 20-20000 vibrations(Hz)

Explain how harmonics and resonance affect the sound from musical instruments - when the instrument has fundamental frequency and whole number multiples of that frequency (complex wave) -unique sound of each instrument comes from the relative intensity of different harmonics in each note RESONANCE - instrument vibrates in response to strings vibrating - natural frequencies: response of instrument to vibrate at certain specific frequencies in tune with the strings - natural frequency: instrument’s mass, shape and size, medium - amplified- instruments need this if do not resonate well How instruments work: - grouped strings, air, column, membranes - work by standing waves: - change pitch by changing length of strings, or opening of holes - Fundamental frequency: frequency of the string’s vibrations

Describe the function of the ear

Explain how sonar and ultrasound imaging work (sound navigation and ranging) a. Distance to ocean floor D=1/2vt b. organisms that use sonar: bats, dolphins, whales

ULTRASOUND IMAGING SONOGRAMS frequency of 1 million-15 million Hz A. MEDICAL USES OF: a. diagnose problems b. guide surgical procedure c. view unborn fetuses B. NONMEDICAL USES OF: a. locate hairline fractures in metal support beams and machinery b. clean jewelry, dentures, and small machinery 2. ADVANTAGE of ultra vs x-ray a. doesn’t harm living cells

Section 12.1 review questions What is the human range of hearing? Musical instruments produce ___waves? What does harmonics do for instruments? What does resonance do for instruments? Medium Speed of sound Gases Liquids solids

Review for Ear What is sonar? Name 3 organisms that use sonar. Give the formula used to determine depth using sonar. What is a sonogram? Name 5 medical uses of Sonar. What is the advantage of sonar over x-rays? Name 3 nonmedical uses of Sonar Try to sketch and label from memory the parts of the ear. Name the regions of the ear? Where does resonance occur in the ear?

Recognize that light has both wave and particle characteristics Wave characteristics a. 1801 Thomas Young interference pattern in light so modeled wave b. model supported by interference, reflection, and refraction Particle characteristics a. 1905 Albert Einstein explain photoelectric effect b. photons are bundles of energy which can eject elecrtons from a metal plate c. model is supported by dim blue light knocking electrons off a metal plate while bright red light cannot. d. Explains how light can travel without a medium

Relate the energy of light to the frequency of electromagnetic waves

Electromagnetic spectrum

Uses of electromagnetic waves

Review for section 12.2 Light is described as a transverse wave that doesn’t require a ______ to travel Who introduced photons? Photons do not have mass, they are more like little bundles of ______. Most scientists accept both models of light. Some believe that light has a “_______ ______” Speed depends on _____. What happens to speed of light as medium density increases? Brightness depends on ______ or the number of photons or waves.

PORTION OF ELECTROMAGNETIC SPECTRUM OCCURANCES PORTION OF ELECTROMAGNETIC SPECTRUM RADAR SMALLEST PORTION OF THE ES TELECOMMUNICATION HIGHEST ENERGY WAVES TV SIGNALS CAUSES SUNBURN USED BY RESTAURANTS TO KEEP FOOD WARM HEAT AM/FM USE SUNSCREEN FOR PROTECTION IMMEDIATELY ABOVE VISIBLE LIGHT IN THE ES SHORTEST WAVELENGTH COOKING LONGEST WAVELENGTH CAN PRODUCE IMAGES OF BODY ORGANS

Describe how light reflects off smooth and rough surfaces Smooth Surfaces: A. light rays are reflected in one direction a. angle of incidence: striking surface rays b. angle of reflection: reflecting light rays c. normal: line perpendicular to the surface at the point where the light hits the mirror. Rough surfaces: a. Diffuse reflection: Light rays are reflected in many directions

Explain the law of reflection THE ANGLE OF INCIDENCE EQUALS THE ANGLE OF REFLECTION - Angle of incidence and angle of reflection are measured from the normal, not from the surface of the mirror

Show how mirrors form real and virtual images Flat mirrors form virtual images by reflection a. virtual image: an image that forms at a point from which light rays appear to come but do not actually come b. appears to exist in a certain place but there are no light rays there 2. Curved mirrors distort images convex mirrors: bulge out concave mirrors: indented in 3. Concave mirrors create real images a. real image: an image of an object formed by many light rays coming together in a specific location b. light rays really exist at the a point where the image appears

Explain why objects appear to be different colors Objects have color because they reflect certain wavelengths of light( all other light is absorbed) a. brain receives signals from certain comb. of photoreceptors cells in the retina b. receptors are three kinds of cone cells, one each for red, green, and blue. c. Color is just the way our brain interpret certain signals

Describe how colors may be added or subtracted Additive primary colors: red, green and blue Secondary colors: yellow, cyan, and magenta Subtractive primary colors: reverse secondary colors to reproduce primary Black: the absence of color

http://www.sciencemuseum.org.uk/on-line/outofsight/illusions.asp