when the earth first formed water vapor came from many volcanoes because the earth was trying to cool down. water vapor formed clouds, clouds made rain, and when it rained, it accumulated to where the oceans are, and when rain fell on rocks that contain salt, it took the minerals with it, and made the water salty. Some parts of the ocean are more salty than others because there is more runoff from rocks that contain salt in certain areas than inWhalecum to the forums madam.