EXPERIMENTAR & PROVAR both mean: to try out, to try on, to sample, to test
Experimentar has the additional meaning of: to experiment
Provar has the additional meaning of: to prove.
Eu vou provar esse vinho. (I'm going to sample this wine.)
Quer experimentar a caipirinha? (Do you want to try the caipirinha?)
Posso provar essas roupas? (Can I try on these clothes?)
Use these to talk about trying clothes on, sampling foods trying new things.