Agenda: Waves and Sound quiz next Wednesday Do this:Take out your Homework. Title page 58-59 “Sound Notes Day 2”

Standard: Explore the wave nature of sound and electromagnetic radiation. What am I learning today? How do sound waves travel?

What will I do to show that I learned it What will I do to show that I learned it? I will write a summary of my notes on the Doppler Effect and Wave Interactions

Sound Travel Extension

How does sound travel through different states of matter?

Sound travels through all forms of matter.

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

What Forms of Matter can Sound Travel Through? Gas: sound travels easily through gases It travels about 1,129 feet per second through air. (That’s how fast it travels when you talk!) Liquids: Sound travels through water about 4,794 feet per second. (Think of what ripples look like in the water and how they spread.) Solids: Sound travels through a solid like wood at a rate of 12,620 feet per second. Sound travels fastest through solids! Sound cannot travel through a vacuum (a space that is “empty” of matter).

Breaking the Sound Barrier “Sonic Boom” http://www.youtube.com/watch?v=-d9A2oq1N38

Why does sound travel fastest in a solid?

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 =

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

Sound travels fastest through solids

Vacuum: a place where there are NO molecules (outer space) *There is no sound in outer space because there are no molecules (there is NO matter)

What do you think? 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?

Bell in a Bell Jar https://www.youtube.com/watch?v=ce7AMJdq0Gw

The Doppler WHAT?

The Doppler Effect http://www.youtube.com/watch?v=h4OnBYrbCjY

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

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

The Doppler Effect Draw this now!...

The Doppler Effect “Big Bang Theory – Doppler Effect” http://www.youtube.com/watch?v=z0EaoilzgGE

What are the interactions sound waves undergo?

Reflect/Absorb

*reflection: the bouncing of sound off of a surface

*absorption: the disappearance of a sound wave into a surface

*The harder the surface, the more sound is reflected.

*The softer the surface, the more sound is absorbed.

Echo…Echo…Echo…Echo

echo: a reflected sound wave

Echo = Communication

sonar and echolocation are both the finding of an object using reflected sound

*echolocation= dolphins, bats So…What’s the difference between sonar and echolocation? *sonar = ships, submarines Warships using sonar to find submarines. It’s thought the war ships sonar disrupts dolphins ultrasound system. *echolocation= dolphins, bats

Resonance A phenomenon that occurs when two objects naturally vibrate at the same frequency. The sound produced by one object causes the other object to vibrate. Musical instruments use resonance to generate sounds. An acoustic guitar has a hollow body that amplifies the sounds.

Summarize your notes The Doppler Effect Wave Interactions

Interference Constructive interference-when a compression from one wave overlaps the compression of another wave. Destructive interference-the compression of one wave overlaps the rarefaction of another wave.

Sound Waves Videos: Echoes “The Boy Who Could See Like a Bat” (3:53) http://www.youtube.com/watch?v=r9mvRRwu5Gw Real Life Bat Man (2:54) http://www.youtube.com/watch?v=vpxEmD0gu0Q “Quack Science” video on discovery education (21 min) https://app.discoveryeducation.com/search?Ntt=quack+science