The device is turned on by tapping one side of the frame. When you say "Okay Glass" the screen shows a range of options, including search the web, take a picture, take video, send a message, and search for directions. Swiping the frame with a finger scrolls the menu up and down.

Google Glass transmits sound through vibration against the head. It has a medium-resolution camera -- about five megapixels -- and the projected image is like watching an iPhone screen.

Seth Rosenblatt, senior writer for Cnet News, says while it's interesting to be able to do Internet-related tasks with nothing in your hand, wearing the device in public attracts a lot of attention.

"They've done something very interesting with technology, but in terms of social interactions they've got a very long way ahead of them," he said.

Rosenblatt says its real potential will be tested by the public.

"I think the real test for Google Glass is going to be out on the street," he said. "How are average people going to react when they're forced to interact with somebody wearing Google Glass?

Google says it is still testing the wearable computer, which runs on Google's Android operating system, and is expected to be available by early next year.