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Waves, Sound (Ear), Light (Eye) Study Guide Answers
Vocabulary you need to know:
Medium- a substance through which a wave moves.
Reflection-the bouncing back of a wave after it strikes a barrier.
Vibration- A rapid back and forth motion.
Wave- a disturbance that transfers energy from one place to another without requiring matter to move the entire distance.
Transverse Wave: a type of wave in which the disturbance moves at right angles, or perpendicular, to the direction in which the wave travels.
Diffraction: the spreading out of a wave as they pass through an opening or around the edges of an obstacle.
Image: a picture of an object formed by rays of light.
Pitch: highness or lowness of a sound. Pitch is associated with the frequency of a sound.
Frequency: the number of waves that pass a fixed point in a given amount of time.
Hertz(Hz): the unit used to measure frequency.
Lens: a transparent optical tool that refracts light. (there is a lens found in the human eye).
Refraction: the bending of a wave as it crosses the boundary between two mediums at an angle other than 90 degrees.
Trough: the lowest point of a wave
Wavelength: the distance from one wave peak or crest to the next pear or crest.
Electromagnetic wave: a type of wave, such as a light wave or a radio wave, that does not require a medium to travel; a disturbance that transfers energy through a field.
Longitudinal Wave: a type of wave in which the disturbance moves in the same direction that
the wave travels.
Conduction: the process that moves energy from one object to another when they are touching physically.
Radiation: energy that travels as electromagnetic waves, which include visible light, microwaves, and infrared light.
Convection: The process that transfers energy by the movement of large numbers of particles in the same direction within a liquid or gas.
Conductors: materials that transfer energy easily (heat or electricity, usually metals)
Insulators: poor conductors; they do not transfer energy easily (glass, plastic, wood, air, foam, and paper).
Concepts you need to understand:
1) What is a longitudinal wave? What is a transverse wave? (14C)
Longitudinal waves move (back and forth) in the same direction as the disturbance and in transverse waves (up and down), the direction in which the wave travels is perpendicular, or at right angles, to the direction of the disturbance.
2) What are two ways to classify a wave? (12C)
One way to classify waves is according to the medium through which they travel. Another way to classify waves is by how they move.
3) Draw a wave and label the crest, trough, amplitude, and wavelength. (17C)
4) What is the equation used to measure speed? (20C)
Speed = wavelength x frequency
5) What is a sound produced by? (38C)
Sound is produced by vibrations through a medium.
6) What causes sound to be produced when you speak? (38C)
The vibration of your vocal cords.
7) Explain how sound waves are detected by your ear. (39C)
Your outer ear collects sound waves and reflects them into a tiny tube called the ear canal. At the end of the ear canal is a thin, skin-like membrane stretched tightly over the opening, called the eardrum. The sound waves cause the eardrum to vibrate causing the three tiny bones inside your ear to move (hammer, anvil, and stirrup). The stirrup then strikes the cochlea causing the tiny hair cells found inside the cochlea to vibrate. These cells then sends the signal to the brain via the auditory nerve.
8) Be able to label the different parts of the ear and explain what each part does. (outer ear, middle ear, inner ear, ear canal, ear drum, and cochlea) (39C)
9) Name the two factors that affect the speed of sound? (42C)
The medium the sound is traveling through and the temperature of the medium the sound is traveling though.
10) Name three animals that can hear frequencies above those of what humans can hear. What range of frequencies can humans hear?(47C)
Three animals that can hear frequencies above those of what humans can are include dog, bat, and porpoise.
The range of frequencies that humans can hear are 20 – 20,000 Hz
11) What are the three main types of musical instruments? (61C)
Stringed, wind, and percussion
12) Be able to label the different parts of the eye including the retina, cornea, pupil, and lens. (127C)
13) What is the difference between rod and cone cells found in the retina? (128C)
Rod cells distinguish between black, white, and shades of grays.
Cone cells respond to different wavelengths of light, so they detect color.
14) What causes people with nearsightedness to see blurry images of objects at a distance? Farsightedness to see blurry images of objects up close? (129C)
Nearsightedness occurs when the lens of the eye focuses the image in front of the retina. The farther away the object is, the farther the image in front of the retina the image forms.
Farsightedness occurs when the lens of the eye focuses an object’s image behind the retina. The closer the object is, the farther behind the retina the image forms.
15) Name and explain two ways that doctors can change the way the cornea refracts light to correct vision. (130C)
Wearing glasses/contacts or surgery to change the shape of the cornea.
16) How does heat travel?
Heat travels from objects of at higher (warmer) temperature to objects at a lower (cooler) temperature. This transfer of energy can be done in three ways: conduction, convection, and radiation.
17) What are the effects of heat transfer?
Heat is a flow of energy due to temperature differences. This depends on particle movement. More moving particles will increase the temperature of a substance.
18) What are the similarities and differences between convection, radiation, and conduction?
Conduction / Convection / Radiation· Energy transferred by direct contact
· Energy flows directly from warmer object to cooler object
· Can occur within one object
· Continues until object temperatures are equal / · Occurs in gases and liquids
· Movement of large number of particles in same direction
· Occurs due to difference in density
· Cycle occurs while temperature differences exist / · Energy transferred by electromagnetic waves such as light, microwaves, and infrared radiation
· All objects radiate energy
· Can transfer energy through empty space
19. Name 3 ways insulators are used in your everyday life. Electrical wires, handles on pots and pans, insulation in outside walls and roofs of houses, thermos or insulated metal water bottle, sound proofing for rooms, clothing that protects against the cold or wetsuits for scuba diving.