A volcano is an opening in the Earth’s surface that can allow gasses, magma, and ash to escape. Volcanoes are often found where the Earth’s tectonic plates meet. This is also where earthquakes, which can be caused by volcanic eruptions, usually occur.
Both earthquakes and volcanoes frequently occur in an area of the Pacific Ocean basin known as the Ring of Fire, but volcanoes can occur anywhere—even on the ocean floor. Active volcanoes in the U.S. are found primarily in Hawaii, Alaska, California, Oregon, and Washington.
Volcanoes don’t just occur on Earth. The largest known volcano in our solar system is found on Mars.
There are a variety of ways to classify volcanoes. One way is by their activity. Volcanoes are known as:
- Active: These are volcanoes that have erupted in recent history or are showing signs of activity.
- Dormant: These volcanoes are currently quiet but could erupt.
- Extinct: These volcanoes erupted thousands of years ago but are not expected to erupt again.
Another way to classify volcanoes is by their shape. The three main shapes of volcanoes include:
- Cinder cone: These are the simplest types of volcanoes. They are formed by erupting lava that falls back to the ground around the vent as cinders and quickly cools. Over time, these cooled cinders form a cone shape around the volcano vent.
- Composite: These are steep-sided volcanoes made up of layers of volcanic rocks, ash, and debris.
- Shield: These are gently sloping, flat volcanoes shaped like a warrior’s shield. They are made by flowing, cooling lava.
Volcano models are fun to make and show students how they work. Students across the globe have perfected the DIY volcano-erupting project using baking soda and vinegar, pop rocks, and Mentos with soda.