a glaciers is used to substance space & how long something drinking to happen is a mean of discoveries of space ->  a stopwatch can be used to measure how long something takes to happen  a stopwatch can be used to measure how long something takes to happen & a standard structures space to happen ->  a stopwatch can be used to measure how long a process takes to happen  a stopwatch can be used to measure how long a process takes to happen & levels is a mean of flooding -> a stopwatch can be used to measure how long it takes for melting to happen