( ( When ( ( a ( pure crystalline ) ) ( solid ( is heated ) ) ) ) ( , ( ( the ( atoms ( , ( ( ions or ) molecules ) ) ) ) ( ( vibrate ( ( more ( and ( more rapidly ) ) ) ( until ( ( at ( a ( definite temperature ) ) ) ( ( ( the ( thermal ( mot ion ) ) ) ( of ( the particles ) ) ) ( becomes ( ( great enough ) ( to ( overcome ( ( the forces ) ( of attraction ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT a) (JJ pure) (NN crystalline)) (ADVP (RB solid)) (VP (VBZ is) (ADJP (JJ heated))))) (, ,) (NP (DT the) (NNS atoms) (, ,) (NNS ions) (CC or) (NNS molecules)) (VP (VBP vibrate) (SBAR (ADVP (RBR more) (CC and) (RBR more) (RB rapidly)) (IN until) (S (PP (IN at) (NP (DT a) (JJ definite) (NN temperature))) (NP (NP (DT the) (JJ thermal) (NN mot) (NN ion)) (PP (IN of) (NP (DT the) (NNS particles)))) (VP (VBZ becomes) (ADJP (JJ great) (RB enough) (S (VP (TO to) (VP (VB overcome) (NP (NP (DT the) (NNS forces)) (PP (IN of) (NP (NN attraction)))))))))))) (. .)))
When a pure crystalline solid is heated, the atoms, ions or molecules vibrate more and more rapidly until at a definite temperature the thermal mot ion of the particles becomes great enough to overcome the forces of attraction.
(ROOT (S (NP (NNP Solid)) (VP (VBZ exists) (SBAR (IN if) (S (NP (NNS particles)) (VP (VBP do) (RB not) (VP (VB have) (NP (ADJP (RB enough) (JJ kinetic)) (NN energy) (S (VP (TO to) (VP (VB overcome) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (NN attraction)) (PP (IN between) (NP (PRP them))))))))))))))) (. .)))