( Motion ( ( is ( ( position change ) ( through time ) ) ) . ) )
(ROOT (S (NP (NNP Motion)) (VP (VBZ is) (NP (NP (NN position) (NN change)) (PP (IN through) (NP (NN time))))) (. .)))
Motion is position change through time.
(ROOT (S (PP (IN In) (NP (NN science))) (, ,) (NP (NN motion)) (VP (VBZ is) (VP (VBN defined) (PP (IN as) (NP (NP (DT a) (NN change)) (PP (IN in) (NP (NN position))))))) (. .)))