What is sound WHAT IS SOUND Sound Waves

What is sound?

WHAT IS SOUND?

Sound Waves Foldable • Record notes in flap labeled “What is Sound? ” • Write the words in red font.

What is sound? Sound is a form of energy, just like electricity and light.

Sound is created by vibrations that produce waves of energy that move through matter

*ALL sound is caused by vibration!

The vibrations travel in waves away from the object.

Sound Wave: is a longitudinal wave that is caused by vibrations traveling through a medium.

Sound Waves are longitudinal (compressional) waves. The molecules are being pressed together as the sound waves move through matter. Longitudinal waves travel through the springs just like sound waves travel through the air.

Compression: the part of a sound wave where the molecules are crowded together

Rarefaction: the part of a sound wave where the molecules are spread apart

Time for a diagram!

Why do you think? Sound waves are ALWAYS longitudinal. However, they are generally represented as transverse waves. What tool do we use to represent them this way?

IT’S EASIER!!! Identifying the amplitude and frequency of a transverse wave is much easier than a longitudinal wave. So computers generally show sound waves as transverse even though they are not.

Medium- a substance through which a wave can travel.

What are the properties of sound waves?

Properties of Sound Pitch = how high or low a sound is trombone violin cello flute

Properties of Sound Pitch depends on frequency

THROWBACK Remember that Frequency is… the number of waves that pass by a point each second

Properties of Sound slinky demo Larger frequency = higher pitch Smaller frequency = lower pitch

High Pitch vs Low Pitch Flute http: //www. youtube. com/watch? v=we. TVPm. Wnl. KE Trombone http: //www. youtube. com/watch? v=bcw. Mov. Q 6 US 0

Notice the amplitude (volume)is the same, but the pitch changes. Low frequency Low Pitch Medium frequency Medium Pitch High frequency High Pitch how do you think opera singers can break glass when hitting high notes?

Pitch that “Hertz” Pitch is measured in hertz (Hz)

Humans can hear sounds that vibrate between 20 times a second (20 Hertz) to about 20, 000 times a second (20, 000 Hertz).

Ultrasonic: a sound that is HIGHER than 20, 000 Hz

Ultrasonic: a sound that is HIGHER than 20, 000 Hz Examples:

Ultrasonic: a sound that is HIGHER than 20, 000 Hz Examples: Bats Dolphin Dogs

Infrasonic: a sound that is LOWER than 20 Hz

Infrasonic: a sound that is LOWER than 20 Hz Examples: Elephants Whales

Can you hear this? medium length clip http: //www. youtu be. com/watch? v= Vxcbpp. CX 6 Rk Can you hear this? short clip http: //www. youtube. co m/watch? v =AXh. Rmv 1 mrs 4 Can you hear this? longest clip http: //www. yout ube. com/watch? v=H-i. CZEl. J 8 m 0

Properties of Sound Loudness measures how well a sound can be heard.

Properties of Sound Loudness depends on amplitude

THROWBACK Remember that Amplitude is… the wave height

Properties of Sound lower amplitude = softer sound higher amplitude = louder sound

Loud sound =

Loud sound = Soft sound =

LOUDNESS! Loudness is measured in decibels

*Pain threshold for hearing is 120 d. B (hearing loss can occur)

Top 10 Loudest Noises 135 -145 decibels 10. concert speakers http: //listverse. com/2007/11/30/top-10 -loudest-noises/

Top 10 Loudest Noises 145 -150 decibels 9. Fireworks http: //listverse. com/2007/11/30/top-10 -loudest-noises/

Top 10 Loudest Noises 150 -155 decibels 8. Gunfire http: //listverse. com/2007/11/30/top-10 -loudest-noises/

Top 10 Loudest Noises 155 -160 decibels 7. NHRA Dragsters http: //listverse. com/2007/11/30/top-10 -loudest-noises/

Top 10 Loudest Noises 165 -170 decibels 6. Space Shuttle When the rockets fire, it is wise and, in fact, fully enforced, that you stand at least a half-mile away

Top 10 Loudest Noises up to 188 decibels 5. The Blue Whale The call of the blue whale reaches levels up to 188 decibels. This extraordinarily loud whistle can be heard for hundreds of miles underwater. The whale is the loudest, and, the largest animal on earth.

Top 10 Loudest Noises 180 decibels 4. Volcano Krakatoa The 1883 eruption generated the loudest sound historically reported at 180 Decibels: the explosion was distinctly heard as far away as 3000 miles. It took the sound 4 hours to travel that distance! People 40 miles away had permanent hearing loss

Top 10 Loudest Noises 210 decibels 3. 1 ton TNT bomb Standing as close as 250 feet away from the impact, the resulting explosion from a 1 ton bomb creates a decibel count of 210. Without sufficient hearing protection, not to mention a complete sound-resistant bunker surrounding you, you could quite literally die from the intense vibrations that would literally shake you apart.

Top 10 Loudest Noises 235 decibels 2. 5. 0 Richter Earthquake A sufficient enough quake to rend the ground and destroy buildings, whole rock, and human life reaches a decibel level of 235. If you are caught in the epicenter and are unlucky enough to not be above the ground in a plane or helicopter, the intense noise and vibrations could kill you long before death by any falling object.

Top 10 Loudest Noises 300 -315 decibels 1. Tunguska Meteor The Tunguska event was a massive explosion that occurred in present day Russia, in 1908. The explosion was most likely caused by a large meteoroid or comet. It was measured with the similar impact of a 1000 -Mega-ton bomb with a decibel rating 300 -315. This is often considered to be the loudest single-event in history

Remember Pitch Frequency Hertz can you think of a fun acronym for remembering these? Loudness Amplitude Decibels

Summarizer Pitch = high or low Loudness= soft or loud 1 3 2 4

pitch. 1 3 2 4 pitch.

Speed of Sound The speed of sound depends on the medium it travels through.

Speed of Sound travels through the air at 343 meters per second light travels at about 300, 000 KILOmeters per second!!!! OR 300, 000 meters per second

Speed of Sound travels through water at 1493 meters per second light travels at about 225, 000 KILOmeters per second!!!! OR 225, 000 meters per second

Speed of Sound travels through steel at 5940 meters per second light can NOT travel through steel

Why does sound travel fastest in a solid?

Sound travels fastest through solids because the molecules are tightly packed together

Sound travels fastest through solids

Summarizer #2 My Top 5 List of “Unpleasant” Sounds What do you think causes a sound to be unpleasant? Do you think the sound is unpleasant due to: ➢ “pitch” ➢ “loudness” or ➢ “association” to something else?

Properties of Sound Video “The Sound of Vomit” on discovery education (21: 51) https: //app. discoveryeducation. com/search? Ntt =the+sound+of+vomit first 5 minutes answers Activator

The Doppler WHAT?

The Doppler Effect: The change in pitch (frequency) as a sound gets closer to you.

The Doppler Effect closer sound gets, *The ______a higher the _______the pitch. further away a sound gets, *The _____ the _______the pitch. lower

The Doppler Effect Draw this now!. . .

The Doppler Effect http: //www. youtube. com/watch? v=h 4 On. BYrb. Cj. Y “Big Bang Theory – Doppler Effect” http: //www. youtube. com/watch? v=z 0 Eaoilzg. GE

Sound Travel

How does sound travel differ through different states of matter?

Journal Work In old Western movies, a cowboy would put his ear against a railroad track to listen for a train in the distance. Why do you think they did this?

Sound travels through all forms of matter.

Why should you not tap on a fish tank?

*Sound travels through all forms of matter.

Sound Waves Graphic Organizer • Record notes in boxes under “Properties of Sound Waves”

Solid- molecules are packed tightly Examples: rock, metal, wood Solid =

Liquid- molecules are close together Example: water Liquid =

Gas- molecules spread apart Example: air Gas =

Vacuum:

Vacuum: a place where there are NO molecules

Vacuum: a place where there are NO molecules (outer space)

*There is no sound in outer space because there are no molecules (matter)

A tiny piece of space junk hits this space shuttle. There are two astronauts in the picture – one inside the capsule, and one outside. Can either of them hear the impact? C

Speed of Sound

Breaking the Sound Barrier “Sonic Boom” http: //www. youtube. com/watch? v=d 9 A 2 oq 1 N 38 “Super Boom Compilations” http: //www. youtube. com/watch? v=BHBev. PYVz a. Y

Sound Waves Videos • Gaggle video: “Julian Treasure: The 4 ways sound affects us” (4: 27) http: //www. youtube. com/watch? v=gya 8 f. RY 4 KQ • “The coolest things sounds waves do” (2: 59) http: //www. youtube. com/watch? v=Ude 8 p. Pjaw. K I