Today we will study sound waves using the following simulation:
Sound
1. Start the simulation (run now) and draw a picture in your notes of what you see.
2. Describe what the black and white semicircles are coming out of the speakers. What do the dark bands represent and what do the white bands represent? Go to this site to figure it out.
3. Click Audio Enabled (put your headphones on!). Increase and decrease the frequency of the sound. What changes happen to the wavelength of the waves coming out of the speaker and what happens to the pitch of the tone you hear as you do this?
4. Draw two pictures in your notes, one with high frequency and one with low frequency.
4. Click “Listener” to hear what the man is hearing. Move him closer and then further from the speaker. Describe the changes in the sound the listener hears.
5. What does a change in amplitude do to the wave? What is the effect on the listener? What happens to the waves? What is the meaning of the darker black and whiter white waves coming out when the amplitude is large?
6. Click the Measure tab. Turn the amplitude all the way up, and the frequency to 100 hz. Measure the wavelength of the sound wave. Draw this in your notes and show the ruler in your notes with what you are measuring.
7. Increase frequency to 200 Hz and measure the wavelength, then 400, then 800. What is the relationship between frequency and wavelength?
8. Pause the simulation, clear the wave, put the ruler so zero is right at the edge of the speaker, start the simulation timer, and then start the simulation. Measure the speed of the wave and calculate the speed of sound in this simulation. You can use the calculator in the Applications folder.
9. Go to the Two Source Interference Tab. With two sources of sound that are identical, this is what happens. Move the man slowly up and down. What do you hear where the waves are clearly visible? What do you hear where the waves are kinda gray?
10. Go to the Listen With Varying Air Pressure Tab and turn on Audio enabled. Click Remove Air From Box and watch the pressure gauge as the air is removed. What happens to the sound the listener can hear?
11. The air in the box turns dark when it is removed, what does this signify in the simulation (go back to question 2 for your answer, or, go back to question 2 to answer it better, it’s about pressure).
12. Add air to the box. Write a statement in your notes about what sound waves travel through and what would you hear if you were standing on the surface of the moon with a loud radio right next to you. Would you hear anything? Why or why not?
