During the hot day, the sea water is cold but the sand on the beach is very hot. Why?

Because the heat reflection on land is very fast and the heat is being absorbed by the land / land only for a short period of time ... therefore the heat of the soil / land is more panans from the water, whereas the water itself is absorbing heat in the asiang day and releasing heat at night .. like in the coastal area, if the night temperature will feel hot while the daytime warm-normal temperature.