This is your chance to experiment as
far as you want!
Take the thickest wire you have and
attach a large piece of plasticine to it (about 2.5cm in diameter,
depending on how thick the wire is).
Then, take a thinner wire with a small
ball of plasticine on it (about 1cm in diameter).
Now, find out what height each wire
needs to be so that they both have the same frequency.