Hanging from the ceiling of the National Geographic Museum just might be a key to making exhibits that are even better and more enjoyable for visitors.

The museum in downtown Washington has installed beacons throughout its “A New Age of Exploration: National Geographic at 125” exhibit so it can deliver information relevant to a visitor, as well as track where visitors spend their time. That way exhibit designers can learn which displays are most popular, and which ones need to be tweaked to better appeal to visitors.

“You’re looking at continually improving your craft,” said Elena Guarinello, an exhibition development manager at National Geographic. “Knowing which areas resonate with people is really going to help us make choices about some of the topics we do.” Alternatively, museums such as a National Geographic could hire an evaluation group to study how visitors interact with the space, but that can be costly.

On Wednesday, National Geographic began handing iPhones to some visitors as they enter the exhibit. The devices display only a National Geographic app, which provides information about the exhibit. As visitors walk into a new section of the exhibit, the iPhone will vibrate to alert them that something new is available on screen. Different content is displayed prominently depending on where in the exhibit the visitor is. The idea is for a visitor to get more information about that painting, sculpture or magazine cover in front of him.

National Geographic is using Radius Networks beacons, which are Bluetooth-powered sensors that plug into outlets in the ceiling. The beacons can detect how many feet away a smartphone is. These beacons — small enough that visitors are unlikely to notice them — basically act as digital tripwires, alerting the National Geographic app to automatically display certain information.

The technology is useful for the staff too, to better learn what visitors like. Guarinello cited the example of a giant globe in the exhibit, which early data has shown to be popular.

“Knowing that people do spend a lot of time here, that’s interesting for me as I talk with my colleagues as they make choices of what to do with our exhibition space,” Guarinello said. “It allows you to challenge your assumptions and kind of step into the visitor’s shoes.”

The beacons will be in use until the exhibit closes Aug. 17. Then the staffers will examine what they’ve learned from the data and plan future uses. Guarinello said it was likely they’d try to incorporate the technology into new exhibits debuting for spring 2015.

She envisions sticking with a set of devices that are handed to visitors rather than requiring them to download apps on their phones, which some museums have done.

“Visitors are reluctant to download things onto their own phone,” she said. “I would always want to have a set of things that, ‘Hey, it’s loaded, it’s ready to go, would you like to use this?’ ”