The sun's energy drives the water cycle, which is the continuous movement of water between the Earth's surface and the atmosphere. Solar radiation heats the oceans, lakes, and rivers, causing water to evaporate and rise into the atmosphere. This water vapor eventually condenses into clouds, which then produce precipitation in the form of rain or snow.

Precipitation that falls on land can either run off into streams and rivers or infiltrate the ground. Infiltrated water becomes groundwater, which is water that is stored in the pores of rocks and soil underground. Groundwater can be found in aquifers, which are underground layers of rock or soil that hold water.

Gravity

Gravity is the force that pulls objects towards the Earth's center. Gravity affects groundwater by causing it to flow downhill. Groundwater flows from high elevations to low elevations, following the contours of the land surface. The slope of the land surface determines the rate of groundwater flow.

Gravity also causes groundwater to be under pressure. The weight of the overlying rock and soil creates pressure on the groundwater, which forces it to flow out of the ground when a well is drilled or a spring is formed.

The Sun and Gravity's Combined Effects on Groundwater

The sun and gravity are the two main forces that drive the movement of groundwater. Solar radiation heats the oceans and lakes, causing water to evaporate and rise into the atmosphere. This water vapor eventually condenses into clouds, which then produce precipitation in the form of rain or snow. Precipitation that falls on land can either run off into streams and rivers or infiltrate the ground. Infiltrated water becomes groundwater, which is water that is stored in the pores of rocks and soil underground. Gravity then causes groundwater to flow downhill, following the contours of the land surface. The slope of the land surface determines the rate of groundwater flow. Gravity also causes groundwater to be under pressure, which forces it to flow out of the ground when a well is drilled or a spring is formed.