1. BirdsEye
Developed by the Cornell Lab of Ornithology, BirdsEye has entries on hundreds of the most frequently seen North American bird species and includes images and bird sounds. It helps to guide avid watchers to birds in their area, based on sightings submitted online to eBird.org, a project of Cornell University and the National Audubon Society. Scientists use these observations to figure out the birds’ range, movements and abundance.

2. Molecules
This app depicts 3-D models of compounds that users can manipulate with their fingers via touch screen. These are more than just pretty pictures—the 3-D structure of a molecule is often crucial to its function, so these models help researchers and amateurs see how they work. “You can show colleagues the structure of a protein wherever you want, such as over lunch,” says Columbia University virologist Vincent Racaniello.

3. Geology
This line of apps from Integrity Logic covering 26 U.S. states provides maps with as many as 50 lay­ers of information, including rock types and ages and the location of seismic faults and past earthquakes. Nonscientists find them helpful, too. Mushroom hunters have used the data on forest fires, as some types grow better after fires, says Integrity Logic founder Max Tardiveau.

4. TimeTree
When did humans and chimps last share a common ancestor? Scan the tree of life to find out using TimeTree. The app, from scientists at the Arizona and Pennsylvania State universities, searches the massive databases at the National Center for Biotechnology Information, which hold information on more than 160,000 organisms. TimeTree returns answers on divergence times within seconds, including citations of scientific papers.

5. IveGot1
Do you want to spot alien invaders? Exotic wildlife such as Burmese pythons and Nile monitors are invading Florida and destroying the ecosystem. To help identify reptiles there, professionals and volunteers can rely on this app, which has photographs of species and data on their features, location, and status as native or exotic.

6. ChemJuice
Want to create your own database of molecules on the fly? With ChemJuice, just drag your finger across the touch screen to draw a chemical bond and tap the screen to delete an atom or bond or change its type. The app can also calculate molecular weight, formula and percent composition by element and e-mail the structure wherever you wish—handy for students and professionals.