Interference of Waves Lab: Teach Grade 12 Physics

[janahan]

Hi, I am a grade 12 physics student and as our final evaluation I must teach a section of our textbook to the class. The section I received was "Interference of Waves" and I must also create some kind of lab or demonstration for the class. My idea so far is to set up two speakers playing the same tone on opposite sides of the class. I am hoping that i can position the speakers so that there is an area of deconstructive interference where the volume of the tone is noticeable lower. I'm just wondering if this would work and what equipment is necessary. Also if you guys have any other ideas of how to get the class involved(other than setting up a water table) it would really help. I have time to set up and test the lab ahead of time as well.
Thanks for any help

 

[Born2bwire]

You should first check the feasibility. You can hear the effect, anyone that has accidentally hooked up their speakers out of phase can attest to it but you should try to set it up to maximize the effect. Find the wavelength of you test sound in air and take a look at the Young's double slit experiment. Use the sound's wavelength in air and you should be able to calculate the angles of the maximum and minimum and use that as a guide. Even better, calculate the angles for multiple frequencies and see if you can accurately predict the minimas and mark them out for your demonstration.