1. At the Bell: Pick up a worksheet at the front of class
Sound Introduction
Lesson Goal: Be able to predict how far a storm is based on temperature and using v=d/t
At the Bell: Pick up a worksheet at the front of class

2. Sound
Sound: Vibrations (energy waves) that travel through a medium. Mechanical wave – requires a medium Longitudinal wave – energy parallel

3. Sound
Compression: region of high molecular density and high air pressure Rarefaction: region of low molecular density and low air pressure

4. How We Hear
Sound waves are gathered by our ears and those pressure waves of energy travel through your ear and are recognized as sound.

5. Too Much Noise: Krakatoa 1883
Sailors 20 miles away
Heard 3000 miles away
Further than NY to LA

6. LRAD

7. Speed of Sound
In a vacuum (like space), light travels at a constant speed of 3 x 108 m/s
That’s 300,000,000 m/s
Do you think the speed of sound is the same as the speed of light? Why?

8. Sound vs. Light

9. Sound vs. Light

10. The Speed of Sound
The speed of sound depends on the medium it travels through and the temperature.
Air (room temperatures 68) – 343 m/s
Water (room temp) – 1490 m/s
Sea water (room temp) – 1530 m/s
Aluminum – 5100 m/s
Copper – 3560 m/s

11. Speed of Sound in Air
v = speed T = temperature in Celsius

12. Speed of Sound in Air
1) What is the speed of a sound wave in the air at 55 degrees Celsius?

13. Speed of Sound in Air
2) What is the speed of a sound wave in the air at -10 degrees Celsius?

14. Finding the Distance to a Storm
You can figure out how far away a storm is using PHYSICS! How do you think we can do this?

15. Finding the Distance from a Storm
3) You hear thunder 10 seconds after you see lightning. How far away is the storm? (use 343 m/s for the speed of sound in this example)

16. Finding the Distance from a Storm
3) You hear thunder 10 seconds after you see lightning. How far away is the storm? (use 343 m/s for the speed of sound in this example)

17. Finding the Distance from a Storm
4) You hear thunder 5 seconds after you see lightning. How far away is the storm? Assume the speed of sound is 343 m/s.

18. Finding the Distance from a Storm
5) You hear thunder 10 seconds after you see lightning. How far away is the storm? How far away is the storm if it is 25 degrees Celsius out? (that’s 77 Fahrenheit)

19. How Far Away Is The Storm On Your Own:
1) You hear thunder 8 seconds after lighting. The speed of sound outside is 343 m/s.
You hear thunder 3 seconds after lightning. The speed of sound outside is 343 m/s.
It is 10 degrees Celsius outside. You hear thunder 3 seconds after you see lightning.
It is 0 degrees Celsius outside. You hear thunder 3 seconds after you see lightning.