Photos: MIT science fair for overachieving teens

Twenty teams from high schools across the United States are showing off their inventions this week during the Lemelson-MIT InvenTeams Odyssey at the Massachusetts Institute of Technology campus in Cambridge. Last fall, each team received a grant of up to $10,000 from the Lemelson-MIT Program to create a solution to a problem they chose.

The three-day event enables students to show off their inventions, which run the gamut from health, safety and environment-oriented gadgets to consumer products and assistance-offering devices.

Palo Alto High School students from California demonstrate the Laser Finger, a head-mounted remote-control device for people who have quadriplegia.

Huntsville High School students from Arkansas show off the inside of a device for locating and communicating with people underground. The device targets cave explorers and rescue teams.

Acton-Boxborough Regional High School students from Massachusetts are about to demonstrate a reusable fire-fighting "grenade." The students worked with Cisco Systems to build it.

Students at Eleanor Roosevelt High School of Greenbelt, Md., show off a Driver Awake device, designed to alert people who are falling asleep at the wheel.

Merrimack High School students from New Hampshire discuss their solar-powered biodiesel processor, which powered their bus to the competition.