Robots, animals, space simulators, musicians, career advisers and a lot of hands-on science activities will be on hand at the Washington Convention Center this weekend, when the third annual USA Science & Engineering Festival ends with a “grand finale expo.” Admission to the expo, aimed at promoting STEM education, is free.

Students from Valley View Elementary School in Prince George’s County enjoyed their visit to the USA Science & Engineering Festival two years ago. (Tracy A. Woodward/The Washington Post)

Among the activities: Pilot a Lockheed Martin space flight simulator or try on the company’s cold-weather gear developed for Antarctic exploration. See how Airwolf makes 3-D printers that make 3-D printers. Build a working robot in less than five minutes at Modular Robotics, or race U.S. Army robots through a maze. See and touch little-known Washington-area plants and animals, courtesy of the Ecological Society of America. Construct elaborate towers taller than yourself with Keva planks (and maybe make them collapse).

Dozens of college teams will be showing their entries in the Environmental Protection Administration’s P3 competition for a sustainable future. (P3? It stands for people, prosperity and the planet.) Check out Clemson’s community-based research called the Vanishing Firefly Project or Princeton’s wind-solar system called “Power-in-a-Box” for off-the-grid communities.

Representatives of academic institutions, government contractors, federal agencies (including the CIA) and other organizations will be there, talking about studying and making a career of science and engineering.