The letters following each Review Question refer to the corresponding Learning Objective from the Chapter Opener. Explain why hot springs form and what makes a geyser erupt. (E)

Hot springs form due to the presence of geothermal heat from Earth's interior. In certain areas, the Earth's crust is thin or has cracks, which allows the heat to rise and warm the underground water. As the water gets heated, it rises to the surface, creating what we call hot springs. The specific geological and hydrological conditions of the region will determine the temperature, mineral content, and flow rate of the hot springs.

A geyser is a unique type of hot spring that periodically erupts, spouting hot water and steam into the air. Geysers require specific conditions to form, which include: 1. A substantial heat source near the Earth's surface. 2. A unique underground plumbing system made of permeable and impermeable rock layers. 3. An abundant water supply.

For a geyser to erupt, the following process occurs: 1. Water from precipitation seeps into the ground and fills the underground reservoir. 2. The heat source warms the water at the bottom of the reservoir, causing it to expand and rise through the geyser's plumbing system. 3. As the hot water rises, pressure decreases, allowing the water to boil and transform into steam. 4. The bubbles of steam force the remaining water to shoot upwards, causing the geyser to erupt. 5. After the eruption, the geyser's reservoir refills, and the cycle begins again. In conclusion, hot springs form due to the presence of geothermal heat warming the underground water. Geysers are a special type of hot spring that erupt periodically due to a unique combination of geological conditions and a specific process that involves the heating, pressure change, and boiling of underground water.