1. Sound

3. Ex. guitarr, the strings vibrate

4. Air-molecules that pusheachotherinto a chainreaction

6. You count the tops of the waves

7. High-pitched sound has a high frequency

10. If the frequency of a guitarr string is 1000 Hz, it means that the string vibrates 1000 times per second

11. The inventor of the frequencyunitwas the German physicist Heinrich Hertz

14. As wegrowolder the limits of the human hearing rangedecrease

15. Sound waves with frequenciesbelow 20 Hz are calledinfrasonic sound

16. Sound waves with frequenciesabove 20 000 Hz are calledultrasonic sound

19. There is a scale to seehow strong different sounds are

22. Sound With Different EmphasisHave Different Frequencies

23. The End