( Evaporation ( ( is ( ( the process ) ( ( by which ) ( water ( ( changes ( from ( a liquid ) ) ) ( to ( a ( ( gas or ) vapor ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Evaporation)) (VP (VBZ is) (NP (NP (DT the) (NN process)) (SBAR (WHPP (IN by) (WHNP (WDT which))) (S (NP (NN water)) (VP (VBZ changes) (PP (IN from) (NP (DT a) (NN liquid))) (PP (TO to) (NP (DT a) (NN gas) (CC or) (NN vapor)))))))) (. .)))
Evaporation is the process by which water changes from a liquid to a gas or vapor.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (JJ liquid) (NN water) (NNS changes)) (VP (TO to) (VP (VB water) (NP (NN vapor)))))) (NP (PRP it)) (VP (VBZ is) (VP (VBN called) (NP (NN evaporation)))) (. .)))
When liquid water changes to water vapor it is called evaporation.