Experimental computational physics using an inexpensive microcomputer

The laboratory for the computational physics course at Texas Tech University has been designed around the Radio Shack TRS‐80 Color Computer. The nominal price of about $100 and the flexibility of its Motorola components make this microcomputer well suited to pedagogical experiments involving data acquisition and processing. An impressive amount of real time computing can be performed using the machine’s internal clock. An example laboratory case is described in which period and amplitude of a simple pendulum are measured sequentially using a machine language timing routine. During the time interval between measurements, a BASIC routine corrects the period of the pendulum for amplitude departure from isochronism. This ‘‘zero amplitude’’ period is printed between measurements, and a ‘‘running’’ estimate of its mean value is maintained and printed after the last measurement.