Is period the same as time with standing waves? I did ten oscillations with a one hump standing wave and I timed it to get an average of 7.37 seconds. Would that be the wave's period?

An insulated thermos contains 148 g of water at 72.7 ˚c. you put in a 11.7 g ice cube at 0.00 ˚c to form a system of ice + original water. the specific heat of liquid water is 4190 j/kg•k; and the heat of fusion of water is 333 kj/kg. what is the net entropy change of the system from then until the system reaches the final (equilibrium) temperature?