Two computer-assisted experiments are described: (i) determination of the speed of ultrasound waves in water and (ii) measurement of the thermal expansion of an aluminum-based alloy. A new data-acquisition system developed by PASCO scientific is used. In both experiments, the "Keep" mode of recording data is employed: the data are recorded only when commanded. This allows one to record one variable automatically while the second variable is introduced by hand. The experiments are recommended for undergraduate laboratories.