Science Buddies: "Ask an Expert"

Hi. I've been following your "Guitar Fundamentals: Wavelength, Frequency, & Speed" project for a science fair. I already have the measurements & frequencies down. The only thing I have left is to find the velocity and wavelengths of a wave on a vibrating guitar string. I don't really understand what I'm supposed to be doing with the formula, so I took a guess at it. This is what I got for the first fret of the Low E string on the guitar: if v = fλ, and the wavelength of the lowest frequency on a string is twice the length of the string, (3.8 cm) then I should get the wavelength (7.6 m/s)? If I multiply that by the frequency of the note (164.98 hz), I should get the velocity (1253.85 m/s)? I'm not really sure if that's right or not, so any help would be greatly appreciated. Thanks so much.

Hi musicnerd1,

Just applying a reasonability test 1253.85 m/s can't be the correct answer. It's a very high speed! 1253.85 cm/s or 12.5385 m/s sounds more reasonable.

Thank you so much, davidkallman.
I knew something didn't look right with it, and I really appreciate the help. :]

Dear Musicnerd1!

I am reviewing some past e-mail questions.
Your question about guitar string velocity hit me. because one of the most persistant problems in calculations is keeping the units (cm, m, mi, s, ft ,,etc) accurate and consistent.

One precaution I adopted was writing the units down next to each number so there could be no ambiguity in the factors used in the equations.