Subject: How do I get 1 plant to here music but make sure the other dosen't

I'am an 8th grader and in honor science so I have to do A science Fair 
Project this year(it is my first one). I'am reachering, Does music have an 
effect on a plants growth by using 2 plants one as an independent varible 
and the other as the dependent variable. i have a pretty good idea of 
making sure that the other plant dosen't here music, but I'am not quite 
sure if it is going to work, I though of using headphones and putting it 
on the plastic flower pot so that the other one wont here anything, but my 
dad said that the other plant will still hear the music, so that's where 
you come in, do you think that will work? another factor I'm trying 
analyze is where am I going to keep these plants so that they only here 
music when i put it on.  I thought of my room and keeping it on my window 
seil for 3 monthes till it is due so that it stays alive, but how do i 
make sure when I'am testing one of  them, that both of them get the same 
amount of light.
                      Thanks

Re: How do I get 1 plant to here music but make sure the other dosen't