Points to Remember, Glossary, Concept Map

Points to Remember

• Sound is produced by the vibration of the particles of a medium.

• Sound is a form of energy that is transferred as vibrations through the air or any other medium, in the form of waves.

• In a wave motion only the energy is transferred not the particles.

• The distance between two consecutive particles which are in same phase of vibration is called wavelength.

• The time taken by a vibrating particle to complete one vibration is known as time period of the vibration.

• The speed of a wave is the distance travelled by it in one second.

• Higher the frequency of sound, higher will be the pitch.

• The speed of sound increases with increase in humidity.

• Music is produced by the regular patterns of vibrations.

• Sound with the frequency ranging from 20 Hz to 20000 Hz is called sonic sound or audible sound.

• A sound with a frequency below 20 Hz is called as subsonic or infrasonic sound.

• A sound with a frequency greater than 20000 Hz is called as ultrasonic sound.

GLOSSARY

1. Amplitude The measure of a sound wave.

2. Pitch How high or low a sound is. It is determined by the frequency of the vibration.

3. Sonic Boom A shock wave that consists of compressed sound waves created when

something moves faster than the speed of sound.

4. Sound Wave Moving pattern of high and low pressure or vibrations.

5. Speed of Sound How fast sound moves through an object.

6. Vibration Back and forth motion.

7. Wavelength The length between the compressions in a sound wave.

Concept Map

REFERENCE BOOKS

1. The everyday physics of hearing and vision by Bejamin de Mayo

2. Vibration and Waves by Anthony French

INTERNET RESOURCES

1. www.pbslearningmedia. org

2. www.scholastic. com

ICT CORNER

Sound

Make simple science toys from trash and enjoy the sounds so produced.

Step 1 Open the browser and type the URL or scan the QR code given below.

Step 2 Toys from Trash page will open. Simple science toys will appear under the heading ‘Simple Sounds’.

Step 3 Click on the Icons to learn the step by step procedure for making simple sounds toys. Enjoy making and playing with various sound producing toys.

Web URL:

http://www.arvindguptatoys.com/simple-sounds.php

*Pictures are indicatives only.

*If browser requires, allow Flash Player or Java Script to load the page