Tom Zinnen is a big fan of former UW President Charles Van Hise’s 1904 speech in which he articulated what would famously become the Wisconsin Idea.

Van Hise said he would never be content until the “beneficent influence of the university reaches every family of the state.”

Today, the UW can use its “beneficent influence” to teach “science savvy,” so Wisconsin residents are able to use science to their advantage, said Zinnen, a UW-Madison scientist organizing the large science open house this weekend on campus.

That’s also the idea behind Science Expeditions, UW-Madison’s 15th annual free scientific open house, taking place Friday through Sunday at 21 locations on the UW-Madison campus.

The weekend will feature demonstrations, hands-on activities, tours, shows and films.

Science Expeditions is geared towards all, but tends to draw families with preschool- to middle school-aged children because most events take place on Saturday and Sunday, the days science-minded parents and grandparents routinely bring children to campus for science events.

Those events include the popular monthly Saturday Science sessions and the celebrated six-year-old Wisconsin Science Festival held in October.

“There’s nothing I can think of that is more valuable that we as scientists have to share with the general public than the ways that we view and do science as exploring the unknown,” said Zinnen, a UW-Extension specialist with the UW-Madison Biotechnology Center.

While the bulk of activities and events happens Saturday, Science Expeditions kicks off at 6:30 p.m. Friday with a Joy of Origami workshop led by Wisconsin Public Radio host Ruthanne Bessman. Visitors will learn the art and science of paper folding in Room 1360 of the Genetics Biotechnology Center, 425 Henry Mall.

From 7 to 9 p.m. Friday, geophysicist Bob Schneiker will give a presentation on the geologic history of the Egyptian Sphinx.

On Saturday, Zinnen is particularly looking forward to Science “Scinema,” when a number of short documentaries from the Howard Hughes Medical Institute will be shown from 10 a.m. to 4 p.m. in Room 1111 of the Genetics Biotechnology Center.

At 7 p.m. Saturday, two UW-Madison alumni from the studio that produced the films, Dennis Liu and Laura Helft, will discuss how they made them.

“For me, I think the big thing is, not only do people get to watch the movies, but they get to talk to producers about what it takes to make a compelling story about researchers in the field,” Zinnen said.

Also on Saturday, visitors will have an easier time getting into the big, popular, UW science presentations “Science is Fun,” and “The Wonders of Physics,” where normally the free tickets get snatched up well in advance. For Science Expeditions, tickets for both shows are handed out on a first-come, first-served basis.

The “Science is Fun Spectacular” will take place at 3 p.m. in the Chemistry Building, Room 1351, at 1101 University Ave. “The Wonders of Physics” will explore the “physics of plasma,” at 10:30 a.m. and again at noon in Chamberlin Hall, 1150 University Ave.

An hour-long chemistry show presented by students takes place at 1 p.m. Saturday in Room 1351 of the Chemistry Building.

Chemistry professor Bassam Shakhashiri made “Science is Fun” a blockbuster and physics professor Clint Sprott did the same for “The Wonders of Physics.”

Shakhashiri, 77, has presented his well-known “Once Upon a Christmas Cheery, In the Lab of Shakhashiri,” every December for 47 years. He’ll be in San Francisco giving lectures Saturday, but said his “well-trained and experienced Science Is Fun group” will carry on without him.

Meanwhile, Max Turner, outreach coordinator for “The Wonders of Physics,” will be emceeing the plasma show for Sprott on Saturday for the first time.

Sprott, 74, an emeritus professor who retired in 2008, also will be out of town on Saturday, and not present for the show. Still, he is very much involved in “The Wonders of Physics” and hosts the big annual shows every February. He only rarely participates in the many other presentations of “The Wonders of Physics” done throughout the year, he said.

The show just completed its 34th season with the 297th show in the series.

The Science Expeditions are merging with Saturday Science — held in the Wisconsin Institutes for Discovery the first Saturday of the month — just for April, and that’s by design, Zinnen said. The WID building, 330 N. Orchard St., will be a hub of activity, with four dozen exploration stations for all ages from 10 a.m. to 2 p.m. Saturday.

Also on Saturday, the UW Planetarium will show a 20-minute film, “Chasing the Ghost Particle,” which offers views of the galaxies around us, and a peek inside IceCube, which is looking for traces of neutrino collisions at the South Pole. The film runs on the hour from 11 a.m. to 3 p.m., at the Sterling Hall Planetarium, 475 N. Charter St.

Since 2001, UW-Madison researchers have been involved in the search for a cosmic particle, which could be a key in discovering the origin of dark matter and other secrets to the universe.

For a full schedule of events, visit: www.science.wisc.edu/events-science-expeditions.htm

The events are expected to draw between 2,500 and 3,000 people on Saturday, and about half that number on Sunday. A free trolley will run between venues on Saturday and Sunday.

The point of having an open house is to give people “a chance to connect to the remarkable constellation” of scientists, programs and venues “on their public, land grant research university,” Zinnen said.

He emphasized that the connection should really last more than just the three days of the open house.

“It’s connecting to these resources for the other 362 days out of the year, and how can you do this in person by coming to campus or connecting to websites and things you can watch on Wisconsin Public Television, like ‘Wednesday Night @ the Lab,’ “ he said.