WASHINGTON - When Easton LaChappelle met President Barack Obama at the White House on Monday, the Mancos High School junior offered him two handshakes.

One with his real arm, and another with a robotic one.

Easton, 17, a Mancos High School junior, first came up with the idea of the brain-controlled, wireless arm - which he shows off on a tall stand - when he was 14. On Monday, he brought his invention to Washington, D.C., for the White House Science Fair.

The Science Fair showcased 100 students from across the country and their science, technology, engineering and math projects, according to a press release.

"Let me just start by saying, in my official capacity as president: This stuff is really cool," Obama said in his remarks in the East Room. "And I want to thank these incredible young people for explaining to me what the heck is going on."

Obama singled out several students in his speech, including Cheyenne Mountain High School senior Sara Volz, 17, of Colorado Springs. Sara researched algae biofuels in her bedroom laboratory - she conducted her experiments under her lofted bed.

"So, Sara, you have very supportive parents. One reporter asked her, 'Exactly what is growing under your bed that's going to save the planet?'" Obama said as he asked her to rise from her seat. "And Sara's answer was algae that can produce more oil for cheaper biofuels."

"Fuel from pond scum - how is that not the most exciting thing ever?" Sara said in an interview in the Blue Room, her DNA double-helix earrings bobbing.

Easton also has a bedroom laboratory, but his prosthetic arm didn't require any algae growth. He built the arm - which can be controlled by thoughts, different facial expressions and blinking patterns from 10 feet away - using a 3-D printer.

He's already been featured on Nickelodeon and in the magazine Popular Mechanics. PBS hopes to do a documentary about him.

Easton spent all last week at home preparing for the science fair. He toted it through airport - part of his carry-on luggage - and U.S. Secret Service security, already expecting the strange looks he got as it went through X-ray machines.

Once at the White House, Easton set up his station in the State Dining Room with the arm and a posterboard.

But the arm fell off its stand and broke at the elbow joint just before Obama walked over. The president, who had been briefed on the malfunction, asked Easton if it was working.

"Up until two minutes ago," Easton said, according to a press pool report.

But Obama still gave it a handshake, Easton said, and inquired about the future of the arm. The young scientist thinks it can be fixed with some super glue.

Overall, Easton said his trip was "an awesome experience."

"Even just seeing the White House, let alone being in it," he added.

Easton won't be away from the federal government for long: he's already secured an internship with NASA for the summer.