1. Hot Springs

2. Natural flow of underground water to the surface of the Earth Water percolates underground through rock, soil, and sediment Some water may have traveled great distances underground before resurfacing as a spring Underground water is heated geothermally by the mantle (30 – 100°C ) Can occur at volcanic and non-volcanic areas

3. Types of Eruptions Water heats up as it comes into contact with magma If the water becomes so hot that it builds steam pressure and erupts in a jet above the surface of the Earth, it is called a geyser If the water only reaches the surface in the form of steam, it is called a fumarole If the water is mixed with mud and clay, it is called a mud pot

4. Therapeutic Uses Hot springs often have high mineral content in the water, such as calcium, lithium, and sulfur This is because the water absorbs minerals as it percolates through the ground Also, heated water can hold more dissolved solids The water is thought to have therapeutic and medicinal value Thus, many hot springs are visited by tourists from around the world

5. Life Around Springs Organisms that can survive near hot springs are called thermophiles These include various bacteria, algae, and some reptiles

6. Famous Hot Springs Yellowstone, Wyoming Blue Lagoon, Iceland Dallol, Ethiopia