Physics of Sound

1. Physics of Sound Investigation 3: How Sound Travels Part 1 Sounds Through Air and Water

2. 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.

3. Sounds through air and water • When the fire 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 filled with water, would you still be able to hear the bell? • Can sound travel through water?

4. 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 first two stations.

5. 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!

6. 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.

7. Recording sheets • You will need to you science book for each mini-activity. • There is s recording sheet to fill out for each mini-activity. • Read the directions CAREFULLY and RECORD your observations!

8. Discuss observations • What did you observe while doing the activities? • What did you see? • What did you hear?

9. 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?

10. Megaphone • Somehow we need to make the sound louder. To make sound louder is to amplify sound. • This is amegaphone. I can use this megaphone on my ear to amplify the tone-generator sound. • How do you think the megaphone works?

11. 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?

12. 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.

13. 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.

14. 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.

15. 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.