As iPad applications go, "Lewis Dots" is basic. It lets students build and manipulate chemical bonds, replacing the pencil and paper diagrams generations of chemistry students have drawn.

But students say the touchscreen makes adding atoms and matching electrons easier to compute.

"I'm a visual learner, so I can see it on the iPad and touch it, and I know what bonds go together," says student Ebony Harris.

"It's so visual and it's like you're having fun doing the work instead of just writing it out and memorizing it," says student Sadia Akhtar.

The city is encouraging schools to incorporate technology into lessons, and the market is flooded with new applications, computer programs and devices for interactive learning. New tools can be promising, but many are also untested and expensive.

"Lewis Dots" does not try to revolutionize the way chemistry is taught and learned, but just updates it. It is also free, because it was developed by scientists at New York University-Polytechnic specifically with the Brooklyn students in mind.

"I was interested in having girls get into chemistry and science in general," says NYU-Polytechnic Professor Jin Kim Montclare.

Montclare paired her graduate students with an all-girls public school in Brooklyn, the Urban Assembly Institute of Math and Science, and one of their ideas was to develop this app.

"Instead of having it as abstract objects in a textbook or on the blackboard, you have something you can touch with and play with and own it and make," says Montclare.

The girls say it helped. Four of the students say they not only passed, but did well on the Chemistry Regents exam. But they are quick to credit their teacher for their success.

"It had to do with the teacher because she was a fun person, she made learning chemistry fun. The app just made it way easier," said student Elizabeth Adesanya.

Although it was designed for girls in Brooklyn, "Lewis Dots" is available on iTunes. The NYU team say it is being downloaded several hundred times a day.