December 5 th (A day) December 8 th (B day) Study Hall: Work quietly at your seat (homework, study, draw, read) NO TALKING. NO EXCEPTIONS. SIT IN ASSIGNED SEATS.

See if you can determine what the following magnified photos are. Number your paper to 5.

The Answers:

Discovery Ed Video Introduction to Sound Waves

Sound Notes.. Sound

Sound – write these notes Energy: caused by vibrations (movement up or down or back and forth)

Discovery Ed Video Vibration and Sound

Sound Waves – write these notes Amplitude : how loud or soft a sound is (loud sound = large amplitude) (soft sound = small amplitude)

Comparing Amplitude and Sound Which wave is louder, why?

Sound and Volume – write these notes Volume- the loudness or softness of a sound that you hear.

Sound Waves – write these notes Decibels (dB) – measurement of sound Sounds over 120 decibels = dangerous

Sound – write these notes Frequency: number of sound waves in 1 second

Frequency Humans hear frequencies ranging 20 – 20,000 hertz Dogs hear frequencies up to 45,000 hertz (Dog whistle – we humans cannot hear it)

Table of Sound Frequencies

Sound – write these notes Pitch : how high or low a sound is based on how fast something vibrates

Pitch and Sound – write these notes If an object vibrates quickly = it will produce a high-pitched sound ( has high-frequencies and short wavelengths) Example = flute has a higher frequency & pitch

Pitch and Sound – write these notes If an object vibrates slowly = it will produce a low-pitched sound ( has low frequencies and long wavelengths) Example = tuba has a low frequency & pitch

Discovery Ed Video Amplitude, Wavelength, Frequency, Pitch

Sound – write these notes Moves in waves: Longitudinal waves

Sound – write these notes Moves through mediums Sound cannot travel in outer space (vacuum) Solid liquid gas fastest in solids slowest in gases

Examples: Sound in different mediums MediumSpeed Air 740 miles per hour Water 3,324 miles per hour Steel 7,435 miles per hour

Sound – Something can be heard when sound waves enter the ear. The human ear receives sound waves as vibrations Vibrations are converted to signals processed by the brain

Discovery Ed Video “How Do Sound Vibrations Reach Our Ears?”

Human Ear The structure of the ear has many parts, which affects how we hear things.

Parts of the Ear… You will receive a handout detailing the parts of the ear We will investigate a variety of ear parts as you color code each specific part You should have crayons on your desk also

Structures of the Human Ear – follow along on your handout Outer Ear catches sound waves and funnels them into the ear canal where they strike the eardrum (middle ear) Eardrum is a thin, taut membrane which vibrates as sound waves strike As the eardrum vibrates, it causes tiny bones on the other side of the eardrum to vibrate also.

Structures of the Human Ear – follow along on your handout Tiny bones: the hammer, the anvil, and the stirrup amplify, or increase, sound. These bones are attached to the cochlea, which is filled with a liquid that changes vibrations to electrical messages These messages are sent through the auditory nerve to the brain, which interprets the sound.

Diagram of the Ear

Vocal Chords and Sound – write these notes Vocal chords produce sound. Larynx = the voice box. The vocal chords (or vocal folds) are part of the larynx. The larynx sits on the top of the trachea. Trachea = windpipe (the tube that connects your lungs to your throat) The vocal chords vibrate to create the sound of the voice. Put your hand on your throat and hum…you are feeling your vocal chords vibrate!

Vocal Chords and Sound – write these notes Air comes out of the lungs, through the trachea, and into the larynx. The air makes the vocal chords vibrate. When the vocal chords vibrate, they release little puffs of air (beginning of sound waves) The sound waves are enhanced and leave your mouth as sound (your voice)

Vocal Chords

Deafness?? We will have to work on this later in the week Maybe some extension activities which investigate hearing impairments, cochlear implants, etc

FYI - sound More intense vibrations create sound waves with higher amplitudes, leading to sounds with higher volumes. The amplitude of a sound wave decreases as the sound wave travels greater distances, making the volume softer as the distance between the receiver and the vibrating object increases.

Common Misconceptions Students may think sound changes pitch when an object vibrates harder. In fact, an object that vibrates harder will make a louder sound, but the pitch will not change. Students may think that louder sounds travel faster. In fact, loud sounds and soft sound travel at the same speed.

Create a Phone Experiment 2 volunteers to “talk” through our homemade telephone Predict: Will we be able to hear better through our phone?