What Makes the famous Geyser Old Faithful erupt?

Old Faithful is a column of steam and superhot water. ... The water escapes when the ground water is heated to boiling by the hot volcanic rocks below. Expanding steam bubbles push the water overhead through the fissures in the rock until they overflow from the geyser.

How many times a day does Old Faithful erupt?  About 17 times daily!

If you haven't been to America's First National Park yet, you should take a look at the map and plan your trip.  Yellowstone is located at the northwest corner of Wyoming over 2.2 million acres.  Its border spills over into Montana to the north and Idaho to the east ever so slightly.  

Highlights of this wonderous expansive park include:

The Norris Geyser Basin - This basin is the hottest, oldest and most dynamic of Yellowstone's thermal areas.  Norris shows evidence of having had thermal features for at least 115,000 years.

Hayden Valley - Centrally located in Yellowstone Park, Hayden Valley is the place to see wildlife, mammals, birds, fish, reptiles and amphibians.  Featuring bison, elk, and the occasional grizzly bear and plenty of ducks, geese, pelicans.

Grand Prismatic Spring - The largest hot spring in the United States and third largest in the world.  With a depth of 160', its colors match the rainbow dispersion of white light by an optical prism: red, orange, yellow, green, and blue.  

Grand Canyon of the Yellowstone - This grand canyon is the first large canyon on the Yellowstone River downstream from Yellowstone Falls.  Yellowstone river is the force that created the canyon and the falls.  The colors of the canyon are a result of the hydrothermal alteration.  Most of the yellows of the canyon are a result of the iron in the rock.

More amazing highlights of the glorious national park go on to include Yellowstone Lake, Mammoth Hot Springs, Firehole River, and many other sites!  

A travel adventure not to be missed, more information can be found at Yellowstone National Park at: https://www.nps.gov/yell/index.htm