( ( Watch ( ( a video ) ( ( showing solids ) ( expanding ( when ( ( heated and ) ( gases ( ( contracting ( when cooled ) ) ( -LRB- ( ( involves ( ( ( ( fire , ) ( liquid nitrogen ) ) and ) ( a balloon ) ) ) -RRB- ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Watch) (NP (NP (DT a) (NN video)) (VP (VBG showing) (NP (NNS solids)) (S (VP (VBG expanding) (SBAR (WHADVP (WRB when)) (S (S (VP (VBN heated))) (CC and) (S (NP (NNS gases)) (S (VP (VBG contracting) (SBAR (WHADVP (WRB when)) (S (VP (VBD cooled)))) (PRN (-LRB- -LRB-) (S (VP (VBZ involves) (NP (NP (NN fire)) (, ,) (NP (JJ liquid) (NN nitrogen)) (CC and) (NP (DT a) (NN balloon))))) (-RRB- -RRB-)))))))))))) (. .)))
Watch a  video showing solids expanding when heated and gases contracting when cooled  (involves fire, liquid nitrogen and a balloon).
(ROOT (S (NP (NP (DT The) (NN liquid)) (PP (IN in) (NP (DT a) (NN thermometer)))) (VP (VP (VBZ expands)) (CC or) (VP (VBZ contracts) (S (VP (TO to) (VP (VB respond) (PP (TO to) (NP (NN heat) (CC or) (NN cold)))))))) (. .)))