( ( Reference ( Popular ( Mechanics ( , ( July ( 1997 Chilled ) ) ) ) ) ) ( ( mirror ( hygrometer ( ( The ( chilled ( mirror hygrometer ) ) ) ( ( detects ( dew point ) ) ( by ( ( cooling ( ( a ( ( reflective condensation ) surface ) ) ( -LRB- ( ( a mirror ) -RRB- ) ) ) ) ( until ( water ( just ( starts ( to condense ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Reference) (NNP Popular) (NNP Mechanics) (, ,) (NNP July) (CD 1997) (NNP Chilled)) (VP (VBP mirror) (NP (NP (NN hygrometer)) (SBAR (S (NP (DT The) (JJ chilled) (NN mirror) (NN hygrometer)) (VP (VBZ detects) (NP (NN dew) (NN point)) (PP (IN by) (S (VP (VBG cooling) (NP (NP (DT a) (ADJP (JJ reflective) (JJ condensation)) (NN surface)) (PRN (-LRB- -LRB-) (NP (DT a) (NN mirror)) (-RRB- -RRB-))) (SBAR (IN until) (S (NP (NN water)) (ADVP (RB just)) (VP (VBZ starts) (S (VP (TO to) (VP (VB condense))))))))))))))) (. .)))
Reference Popular Mechanics, July 1997 Chilled mirror hygrometer The chilled mirror hygrometer detects  dew point by cooling a reflective condensation surface (a mirror) until water just starts to condense.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT the) (NN water)) (VP (VBP vapor) (PP (IN from) (NP (DT a) (JJ hot) (NN shower) (NNS contacts))) (NP (NP (DT the) (JJR cooler) (NN surface)) (PP (IN of) (NP (DT a) (NN mirror))))))) (, ,) (NP (DT the) (NN result)) (VP (VBZ is) (SBAR (IN that) (S (NP (NNP foggy)) (VP (VBP mirror))))) (. .)))