Old Faithful Geyser
Old Faithful is the most famous geyser in the world, found inside Yellowstone National Park. It is a hole in the ground that shoots a tall fountain of steaming hot water into the sky.
People love it because it erupts again and again on a regular schedule, so you can wait and know it will blow. The water rockets over one hundred feet high while crowds cheer and clap.
The eruptions
Old Faithful erupts about every ninety minutes, shooting thousands of gallons of boiling water into the air. Each show lasts a few minutes and ends with a big cloud of steam.
Why it is so faithful
Deep underground, water is heated by the volcano until it builds up enough pressure to burst out. Because the underground plumbing is steady, rangers can predict the next eruption very closely.
Visiting
A big curved boardwalk with benches lets families sit and watch in comfort and safety. A nearby visitor center shows the next expected eruption time so nobody misses the fun.