General SCI

On this day in 1804, Lewis and Clark started their expedition up the Missouri River near present-day St. Louis, Missouri.

Although the expedition didn’t reach present-day Iowa until about three months later, we're commemorating today’s 216th anniversary of the famed Lewis and Clark Expedition by reaching out to our friends at the Lewis and Clark Interpretation Center in Sioux City to share what’s outside their window.

Captains Meriwether Lewis and William Clark were amateur biologists and zoologists wanting to learn about the plants and animals living within the territory of the Louisiana Purchase. They recorded their detailed observations in journals, which have been visualized as murals at the Lewis and Clark Interpretation Center. These murals give us an artistic representation of what Iowa may have looked like during their expedition more than 200 years ago.

Scenes of soldiers setting up campsites as well as a scene from a successful two-day fishing trip show native Iowa flora (like the purple cone-flower and other prairie plants) and fauna (like fish, which may have included largemouth bass, channel catfish, crayfish and freshwater mussels). 

One image is a soldier overlooking the river. Looking at present-day images of where the Big Sioux River flows into the Missouri River, it’s hard to imagine traveling this expedition without modern transportation, like cars or motorboats, or infrastructure, like bridges!

The "Garden of Discovery" surrounding the Lewis and Clark Interpretation Center includes sculptures of different animal species encountered by the Lewis and Clark Expedition, including some that no longer call Iowa home, such as elk. 

Although the center's building and exhibits are closed, the gardens remains free and open for exploring!

Special thanks to our friends at the Sioux City Lewis and Clark Interpretation Center for sharing their pictures of what’s outside their window and helping us to all Go Beyond with SCI!

One of SCI's most iconic and beloved features, the Foucault (pronounced 'foo koh’) Pendulum is a 235-pound, 17-inch brass ball that demonstrates the rotation of the earth. It hung for more than 30 years in the Science Center of Iowa's former location in Greenwood-Ashworth Park before joining SCI in its downtown location in 2005. 

Suspended from the ceiling by a 41-foot cable, the pendulum maintains its swing from a circular electromagnet at the top that makes sure it doesn’t lose energy with each swing. This keeps it swinging indefinitely in a 7.5-foot arc, knocking over two of its 427 steel pegs every five minutes. 

The Foucault Pendulum was first devised in 1851 by the French physicist Leon Foucault. Foucault was passionate about making the work of scientists understandable to the public, stating "to contribute usefully to the advance of science, one must sometimes not disdain from undertaking simple verifications."

Foucault created his pendulum to demonstrate a visualization of the Earth’s rotation—something that hadn’t been modeled outside of astronomical calculations and observations.

A typical pendulum swings in straight, fixed line (like the pendulum of a grandfather clock). However, Foucault’s pendulum was not fixed in this way. Instead, he suspended a large iron ball and set it swinging along a North-South line. As spectators watched, they saw it slowly turn in a clockwise direction, moving away from the North-South line and tracing its path in the sand below. This demonstration visualized the Earth’s counter-clockwise rotation.

Does SCI’s pendulum keep time with a 24-hour day? In order for a Foucault Pendulum to complete a full 360-degree rotation in an exact 24-hour period, it would need to be located directly on the North Pole. We can, however, calculate the “Pendulum Day” period of SCI’s Foucault Pendulum (or the amount of time it takes to knock down all of the 427 pegs) using what we know about SCI’s pendulum and applying it to Foucault’s formula. We’ll keep our answer secret but encourage you to Go Beyond and try this physical calculation yourself!

For inspiration, here’s a timelapse video of a full Pendulum Day at SCI compressed into 51 seconds. Observe how the pendulum moves around to knock over each peg—and let us know your guesses on the length of a Pendulum Day at SCI!