One way to supervise global warming is to gauge the average temperature of the ocean. Researchers are doing this by evaluating the time it takes sound pulses to travel underwater over large distances. At a depth of around 1000 m, where ocean temperatures hold steady close to 4 degrees Celsius, the average sound speed is 1480m/s. It is acknowledged from laboratory measurements that the sound speed raises 4.0 m/s for every 1.0 degrees Celsius raise in temperature. In one experiment, where sounds produced near California are detected in the South Pacific, the sound waves travel 7900 km.
When the smallest time change which can be reliably detected is 1.0 s, determine the smallest change in average temperature which can be measured?