Sound is a form of energy that travels in longitudinal waves, requiring matter to transmit vibrations between particles. The speed of sound varies according to the medium, being fastest in solids and slowest in gases. Our ears can detect frequencies between 20-20,000 Hz, perceiving variations in pitch from low to high frequencies and loudness from soft to loud amplitudes. Musical instruments produce sound through vibration of different materials, while other technologies like sonar use sound waves for applications such as locating objects underwater.

1. Sound

4. Sound waves travel faster through solids because there are more particles close together to transfer the energy. Sound waves and

7. Waves transport energy without moving matter Watch the 3 red dots You will see them vibrate , but not move with the wave to the end. All the particles are vibrating but stay fixed

12. Compression Where particles are pressed together as the sound wave moves through matter.

15. Longitudinal Wave (Compression Wave) Each wave particle vibrates back and forth in the same direction of the wave.

17. Waves transfer energy without moving matter. Frequency= waves/time If you watch the 3 red dots you will see them vibrate, but not move with the wave to the end.

21. 20 Hz – 20,000 Hz The human ear can only hear sounds between 20Hz and 20,000 Hz (Frequency/Pitch) Below 20 Hz is called infrasound Above 20,000 Hz is called ultrasound

22. Ultrasound sound waves with frequencies above the normal human range of hearing. Sounds in the range from 20,000-100,000Hz Infrasound sounds waves with frequencies below the normal human range of hearing. Sounds in the 0.001 - 20Hz range

24. The Human Ear

25. Amplitude is the maximum distance the particles in a wave vibrate from their rest positions.

28. Loudness of Sound in Decibels Sound Loudness (dbs) Hearing Damage Average Home 40-50 Loud Music 90-100 After long exposure Rock Concert 115-120 Progressive Jet Engine 120-170 Pain

32. Ultrasound (above 20,000 Hz) Ultrasound waves are used in medicine They are also reflected sound waves

34. Transverse waves wave particles vibrate in an up-and-down motion.

39. That’s all folks!