Why do land breezes and sea breezes occur?

 sea breezes occur in areas where a large body of water is located next to land. 
During the day the land becomes warmer than the water. As warm air rises over the land, cold from over the water moves in to fill the space, thus causing a sea breeze. However, during the night, because water holds heat longer than land, the air over the water is warmer than the air over the land. As the warm air over the water rises, the cold air over the land moves in to take it's place, thus causing a land breeze.