( ( Neutrons ( collide ( with ( ( an atom ) ( of ( ( ( 235 U ) , ) ( which ( splits ( into ( two fragments ) ) ) ) ) ) ) ) ) ) ( ( called ( ( ( ( ( fission products ) , ) ( ( producing energy ) ( -LRB- ( heat -RRB- ) ) ) ) and ) ( two ( more neutrons ) ) ) ) . ) )
(ROOT (SINV (S (NP (NNS Neutrons)) (VP (VBP collide) (PP (IN with) (NP (NP (DT an) (NN atom)) (PP (IN of) (NP (NP (NNP 235) (NNP U)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ splits) (PP (IN into) (NP (CD two) (NNS fragments)))))))))))) (VP (VBD called)) (NP (NP (NN fission) (NNS products)) (, ,) (NP (NP (VBG producing) (NN energy)) (PRN (-LRB- -LRB-) (NP (NN heat)) (-RRB- -RRB-))) (CC and) (NP (CD two) (JJR more) (NNS neutrons))) (. .)))
Neutrons collide with an atom of 235 U, which splits into two fragments called fission products , producing energy (heat) and two more neutrons.
(ROOT (S (NP (DT A) (NN neutron)) (VP (VBZ collides) (PP (IN with) (NP (NP (DT an) (NN atom)) (PP (IN of) (NP (ADJP (JJ u-235) (PP (IN during) (NP (DT the) (JJ basic) (JJ nuclear) (NN fission)))) (NN process)))))) (. .)))
A neutron collides with an atom of u-235 during the basic nuclear fission process.