Free
Volcanoes have two natures. For most of their long lives, they are quiet.
When they destroy things, their bad side makes news and history. But we don’t always think of their good side. Volcanoes give us mountains to ski on and lakes to swim in. They also give us hot springs to soak in. Magma contains valuable elements such as gold, silver, and sulfur. As it cools, some of the elements form minerals. They harden in spaces inside the rocks, where miners find them later. Magma also heats water under the ground. We can tap into it to make heat and electricity. That’s called geothermal power. It’s clean and can be renewed. Volcanic areas make special homes for animals and plants. And sometimes, ash and rock preserve clues about life from long ago.
Moneymakers
◀ There are active volcanoes on the island of Java in Indonesia. Farmers there have grown rice on the same land for centuries. On nearby Kalimantan (Borneo), there are no active volcanoes. There, farmers have to move their plots every few years. That’s because plants need certain nutrients from the soil, and rain washes them away. But ash from active volcanoes gives the soil more nutrients. That lets farmers keep planting.
▲ Sulfur is used to make rubber, explosives, and fertilizers. It has no smell of its own. But hot liquid sulfur and hydrogen combine to make hydrogen sulfide. It’s poisonous and smells like rotten eggs. Many volcanoes have a lot of sulfur in them. Without it, there could be no life on Earth.
◀ In Tanzania, Africa, Ol Doinyo Lengai is different from other volcanoes. It’s the only one with ash that turns into sodium bicarbonate. That’s also called baking soda! Wind and water carry the ash to Lake Magadi in Kenya. There, people mine this chemical.
The Heat Is On
In Beppu, Japan, people cook eggs in one of the city’s 4,000 hot springs. The springs are Beppu’s main business. They bring in 12 million visitors a year. An eruption created the springs more than 1,000 years ago. ▶
◀ The Geysers is 90 miles from San Francisco. It’s the world’s biggest geothermal plant. It makes electricity out of steam from the Earth. The steam comes through pipes from wells. It fuels a machine that powers an electrical generator. When the steam cools, it turns into water. The water is pumped back into the Earth, where nature heats it up again.
Exclusive Homes
◀ Imagine diving more than 1.5 miles down into the ocean. There, 12-foot worms hang around the vents of volcanoes. They eat the bacteria growing there. The bacteria thrive in the heat and minerals from volcanoes.
▲ The silversword plant grows only on the volcanic islands of Maui and Hawaii. It’s rare and endangered. It blooms just once during its life of about 10 years.
Buried Treasures
◀ Paleontologists are scientists who study ancient life. In Nebraska, they have found fossils of rhinos, three-toed horses, camels, and other animals. Ten million years ago, a volcano erupted. The ash buried all those creatures. It’s one of the Earth’s largest fossil finds.
In East Africa, a family left footprints in damp volcanic ash. That was more than 3.6 million years ago. The ash hardened, and so did the footprints. This record showed scientists something important. These humans were some of the first to walk upright. The oldest fossils of our ancestors are found all over Africa’s Great Rift Valley. ▶
Check It Out!
What does your pencil point have in common with a diamond?
The point of your pencil is graphite. Diamonds and graphite are the same element, carbon. Carbon turns into a hard diamond, thanks to a volcano. Diamonds form in volcanic rocks deep in the Earth. Strong pressure squeezes carbon atoms into a tight network. They turn into diamond, the hardest substance on Earth. Without this pressure, carbon forms graphite.
