Google's Alternatice to Siri...

Hey, Siri, you better look behind you. Google on Tuesday upgraded its Google Search app for the iPhone and iPad, giving the feature a voice search functionality that poses a challenge to Apple's Siri.

The app, which is available for free download, opens with a "Try our new voice search" message that sits next to an icon of a microphone. Click on the icon and speak your question into your device.

If the answer to your question is short, Google will tell you the answer aloud. If the answer is more complicated, the user will get a list of possible answers and links on the screen.

"Getting an answer is as simple as tapping on the microphone icon and asking a question like, 'Is United Airlines flight 318 on time?' " wrote Kenneth Bongort, a Google search engineer, in a blog post. "You can get answers to an increasingly wide variety of questions thanks to Knowledge Graph, which gives our search technology an understanding of people, places and things in the real world."

Knowledge Graph, which was introduced this past May, first appeared as an extra column on the Google search results pages. It was designed to help the search engine dig deeper into search requests by asking users to be more specific about what they're searching for.

By combining the technology behind Knowledge Graph and voice recognition, Bongort said Google's search app now can answer questions like, "What does Yankee Stadium look like?" and offer up hundreds of pictures.