Select the "Two Sources" screen from the app. Set the frequency slider to about $300$ Hz $.$ Check the "Listener Audio" box so you can hear the sound that is being produced.

Click and drag the listener vertically on the screen. Describe below what you hear as you move the listener up and down in the box below.

What do you think is happening here? State your best answer below.

Select the "Reflection" screen on the app. In the "Sound Mode" box, select "Pulse". Set off one pulse so you can see what happens as the sound wave pulse reflects off the wall.

Change the "Wall Angle" to something else and set off another pulse. Now, set off pulses for several different wall angles and note how the waves reflect off the wall.