SoundNow hear this!

Sound is a form of energy. Other types of energy we will learn about

are heat and light.

What is sound?

Science BenchmarkHeat, light, and sound are all forms of energy... Sound is created by vibration and cannot travel through a vacuum. Pitch is determined by the vibration rate of the sound source

Standard 6 Students will understand properties and behavior of heat, light, and sound.

What you will learn? (Utah curriculum)

Objective 3 Describe the production of sound in terms of vibration of objects that create vibrations in other materials. ◦ Describe how sound is made from vibration and moves

in all directions from the source in waves. ◦ Explain the relationship of the size and shape of a

vibrating object to the pitch of the sound produced. ◦ Relate the volume of a sound to the amount of energy

used to create the vibration of the object producing the sound.

◦ Make a musical instrument and report on how it produces sound.

More of what you will learn…

Musical Instrument Go over musical instrument rubric. Answer questions.

…is a disturbance that travels through a medium as a longitudinal wave (definition).

…is made by vibrations. …travels in waves. …can travel through solids, liquids, and

gases. …is absent from outer space. …travels in all directions. …when the disturbance reaches our ears,

we call it sound.

Sound

Sound travels through the air by spreading out in a series of ripples, like ripples in a pond when you throw a stone. The ripples that disturb the air are called sound waves.

Energy from vibrations stirs up surrounding air molecules, allowing the sound wave to spread out away from the source of the vibration.

How sound travels

1. You beat the drum2. Surface begins to

vibrate3. Air molecules are

disturbed4. When the drum

moves, it pushes molecules together, creating compressions

5. When the molecules are pushed farther apart, rarefactions are created.

One example of how sound waves work (gasses)

http://www.dosits.org/science/sound/howismade/

1. pluck guitar string

2. Causes vibrations3. Vibrations create

rarefactions & compressions

4. Waves travel through air to your ears

Another example

When you knock on a door, the particles of the door vibrate

Vibration causes sound waves that travel through the door

Sound waves reach other side of door

Waves in door travel to air outside door

Examples of sound waves in solids

Have you ever seen someone in a movie put his or her ear on the ground to tell if a train is coming?

The sound of a train travels through the tracks

You might be able to hear distant traffic if you put your ear on the ground (be careful—don’t do this in the street)

More solids

Remember that conductor, medium, insulator, and other “wave” and “heat” vocabulary still apply to sound

Pitch-perception of the frequency of a sound …how high or how low a musical note is Vibration-a repeated back-and-forth or up-

and-down motion …a rapid back and forth movement

Some new vocabulary

Sounds can change in shrillness or deepness- that is, in their pitch.

Pitch is the number of vibrations that makes the sound high or low

When we hear changes in pitch, it means that the sound waves coming to our ears are changing in frequency. Frequency is the number of sound waves that occur in one second.

The higher the frequency is (and the faster it vibrates), the higher the pitch will be.

The lower the frequency is, the lower the pitch will be. Therefore, the slower something vibrates, the lower the

pitch.

More on vocab

High Frequency vs. Low Frequency

What are the differences?

What are the similarities?

The pitch of a sound is determined by the size (length, thickness) of the object making the sound.

The faster something vibrates, the higher the pitch. This is true of the voice boxes of animals.

For example: women usually have shorter vocal cords than men and have higher pitched voices as a result.

Which would produce a higher sound—a thick guitar string or a thin guitar string?

Pitch

Musical sounds have a regular wave pattern. Music is pleasing to our ears.

Noise sounds have an irregular wave pattern. Noise is NOT pleasing to our ears.

Is it Music or Noise?

An echo occurs when sound waves hit a hard object and bounce back.

Sound travels twice the distance when you hear an echo.

Echo

Bats and dolphins use something called echolocation to help them navigate and hunt.

Submarines use sonar to navigate and tohunt.

Police people use radar to find out yourspeed in a car.

Doctors use ultrasound to see into a mother’swomb.

Using an Echo

What happens when sound hits different types of objects?

1. Reflected-It can bounce off if the object is hard.

2. Absorbed-It can get “sucked in” if the object is soft.

What happens to Sound?

Sound travels at about 1,000 feet (1,083 ft)per second through the air.

Compare this to light which travels at 984,000,000 feet per second.

That’s 7 ½ times around the world in one second!

Sound travels at different speeds throughdifferent mediums.

See figure 4 on page 42 of your science book on sound.

The Speed of Sound

Most people can hear sounds from 20 to 18,000 vibrations per second.

As we get older, our ability to hear high notesdecreases.

Loud sounds can cause hearing damage or loss. Your ear has many complicated parts. All the parts must be working well, or you will have

trouble hearing. Remember that your eardrum is a membrane that

can be torn and destroyed if it starts vibrating toofast or strong.

Sound is cool, but be careful. Once your hearing is gone, it is usually gone for good.

The Human Ear

Ear Diagram-Answers

Ear Diagram-in color

Decibels (dB)-the unit we measure sound with

Hertz (hz)-the measurement of sound vibrations per second

Wavelength Compression Rarefraction Amplitude

More vocab

What they look like-

Volume What’s the difference? The more energy a wave

has, the louder it seems. The intensity of a sound is the amount of energy it has. You hear intensity as loudness.

The amplitude (height) is a measurement of the amount of energy a wave has.

Please list 8 inventions that use sound. 1- 2- 3- 4- 5- 6- 7- Eight items must be listed clearly.

Inventions & Sound

Please write a 3 paragraph(s) on why sound is important to our culture. Be sure to answer the following questions in your paragraph…

A paragraph is at least 4 sentences. What would it be like with no sound? (1

para) What would it be like with no music? (1

para) Why is sound and music so important to us

as a society? Why is it important to you? (1 para)

Sound & Our Culture