1. Welcome Back Minions Now we learn about… SOUND!!! (But first a small recap…)

2. Recap: What are waves? A wave is a disturbance that carries energy through matter and space. The matter through which waves move through is called a MEDIUM. It can be a solid, liquid or gas.

3. Mechanical Waves Waves that require a medium are called mechanical waves. Nearly all waves are mechanical waves. Ex: ocean waves, sound waves and seismic waves (earthquakes) Electromagnetic Waves are NOT mechanical waves, so they do not need a medium to travel through!

4. Characteristics of Sound Characteristics of sound –Pitch –Loudness Sound Level

5. Pitch – Description of how high or low the sound seems to a person. – This depends on the frequency of the sound wave.

6. Pitch Normal range of hearing – 20 Hz to 20,000 Hz Sounds below this range is called Infrasound. Sounds above this range is called Ultrasound.

7. Pitch Some other ranges…

8. PITCH Higher Frequency=Higher pitch Lower frequency= Lower pitch

9. Loudness – Perception of the energy of sound – 2 Factors Amount of energy to make the sound Distance from the source of the sound

10. Loudness Energy – Greater the energy, the louder the sound!

11. Loudness Distance – Intensity Closer to source = more intense As you move from source = less intense

12. LOUDNESS Greater Amplitude = Louder sound Smaller amplitude = softer sound

13. SOUND LEVEL A measurement of sound pressures (measured in Decibels (dB))

14. Sound Level Measuring loudness – Decibel How different level of sounds are measured and compared

15. Sound Level Here is a list of ranges…

17. Now the question you want answered… Is there a noise loud enough to kill a person? Link: https://www.youtube.com/watch?v=9zTXiPcpLV0