Final answer:
Seawater remains warm after sunset because of its specific heat capacity. Water's high specific heat allows it to absorb and store sunlight energy during the day, which it then gradually releases throughout the night.
Step-by-step explanation:
The temperature of seawater doesn't cool off immediately after sunset due to the specific heat properties of water. Specific heat is the amount of heat energy required to raise the temperature of a substance per unit of mass. Water has a high specific heat, meaning it can absorb a significant amount of heat energy without a significant rise in temperature, this also means it takes a longer time for water to lose heat. During the day, the seawater absorbs a lot of heat from the sun and it gradually releases this stored heat throughout the night, which makes it feel warm even after sunset.
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