Invest igation 3: How Sound Travels

Part 1

Sounds Through Air and Water

PHYSICS OF SOUND

OBJECTIVES

I can describe what happens to sound when it travels through water.

I can explain how sounds can be amplified in air.

I can explain how ears help us hear.

SOUNDS THROUGH AIR AND WATER

When the fi re alarm rings, how does the sound get

from the alarm to your ears?

Do you think it travels through the walls, or though air?

If this room were fi lled with water, would you still

be able to hear the bell?

Can sound travel through water?

MINI-ACTIVITIES

You will be investigating how sound travels using

four mini-activities.

Each group will do two mini-activities today, and

two on another day.

Pay attention to how the materials are used in the

fi rst two stations.

SOUNDS THROUGH AIR

You will be using the tuning fork for this activity,

Remember to hold the turning fork by the handle,

and strike the wood with one of the tines using a

medium force.

Use the listening tube to direct sounds to your ear.

These are scientific tools- not toys!

SOUNDS THROUGH WATER

You will be using a stethoscope.

Watch carefully how to use a stethoscope correctly.

A stethoscope amplifies sound (makes it louder), be careful not to strike the diaphragm against hard objects while listening.

Watch how to clap with two fingers.

RECORDING SHEETS

You will need to you science book for each mini-

activity.

There is s recording sheet to fi ll out for each mini-

activity.

Read the directions CAREFULLY and RECORD your

observations!

DISCUSS OBSERVATIONS

What did you observe while doing the

activities?

What did you see?

What did you hear?

AMPLIFICATION CHALLENGE

Listen closely as I play the tone generator.

We have a problem here. The volume is very soft. Is there anything you can do at your seats that will allow you to hear the sound?

MEGAPHONE

Somehow we need to make the sound louder. To make sound louder is to amplify sound.

This is a megaphone. I can use this megaphone on my ear to amplify the tone-generator sound.

How do you think the megaphone works?

MEGAPHONE

The megaphone gathers sound waves at its mouth and focuses them down to the ear.

I can also use a megaphone to amplify sound at its source.

I can put this megaphone up to the speaker to amplify the tone generator sound.

How do you think the megaphone works at the source?

THE EAR

Your ears are your sound receivers.Look at your classmates and observe each others’

ears. The outer ear is made of flesh and cartilage. It collects

and directs sounds much like a megaphone or listening tube.

Other parts of the ear are inside our heads and are called the middle and inner ear. From our inner ear, nerves carry the sound message to our brain.

VOCABULARY

A doctor uses a stethoscope to amplify sounds produced inside the body.

Megaphones can collect and focus sound energy to amplify it at the source or receiver.

VOCABULARY

The outer ear is the flap of flesh and cartilage that directs sound vibrations to the inner ear, where nerves transmit messages to the brain.

OBJECTIVES

I can describe what happens to sound when it travels through water.

I can explain how sounds can be amplified in air.

I can explain how ears help us hear.