Do plants grow better in different spectra of light????

[Rob-Smetana at worldnet.att.net]

I am doing a 7th grade science project asking:  Do plants grow
better in different spectra of light?

I had a few questions to ask.

* Has this experiment been done before?  If so, where can I
find the info about it?

* How long will it take for there to be any effect on the
plants?

* Which spectra further plant growth?  Do any spectra harm
plants; do any spectra retard plant gowth?

* How can I get the different light spectra?  How can I
mesure the spectra?

* Do different plants respond to different spectra? In a six
week experiment, which plants should I choose to most quickly
show an effect?