Simplify the following text for a Grade 9 native English-speaking person.
Original: Pierre and Marie Curie 's daughter IrÃ ne Joliot-Curie and their son-in-law FrÃ dÃ ric Joliot-Curie were also physicists involved in the study of radioactivity , and were also awarded the Nobel prize for their work .
Simplified: Pierre and Marie Curie 's daughter IrÃ ne Joliot-Curie and their son-in-law FrÃ dÃ ric Joliot-Curie were also physicists involved in the study of radioactivity . They also were awarded a Nobel prize for their work .