Green forests, emeralds, and limes, OK. But green fire? Kathryn Riley ’10, a visiting assistant professor at Swarthmore, urges her students to study chemistry through an intellectual kaleidoscope. Unlocking the causes of multicolored fire is one such experiment.

“Different metal ions added to the fire absorb energy as heat and then emit energy as light with unique colors—for example, copper produces a beautiful green flame,” says Riley. “The hottest part is the light-blue interior of a flame, with a temperature around 1,500 degrees Celsius.”

Having embraced the liberal arts here as a student, when Riley returned as a faculty member, she wanted to enable her students to view science through multiple lenses and created an Instagram where she posts fire—and other elements—in all their scorching hues.

“Too often students see chemistry as equations and molecules on a page,” she says, “but science is art—and it’s colorful!” —KC

“Green is the color of energy being captured and transformed,” explains Associate Professor of Biology Nick Kaplinsky, a plant molecular geneticist who focuses on plant responses to high temperatures (bit.ly/NKaplinsky).

One peculiar celebrity in his toasty greenhouse is the Amorphophallus titanum—common name corpse flower—whose bloom can reach up to 8 feet tall, but takes up to 10 years to get there.

Its leaves look green because cells in the leaves hold chloroplasts, dynamic little “molecular factories” whose job is to trap the sun’s light energy and turn it into sugar. The chlorophyll in the leaves absorbs deep-blue and red light, Kaplinsky says, making the plant appear green.

In a showy last act when it finally blooms, the corpse flower emits the sharp scent of rotting flesh—a trait designed over millennia to attract the flies that pollinate its flowers. —KC

“I always did like animals that could change color,” says Francis Ge ’17, who collected and studied the nocturnal gray tree frog in Assistant Professor of Biology Alex Baugh’s animal communication seminar. The frog’s name is somewhat misleading, Ge says.

“Each frog has a unique mottled pattern on their dorsal side that ranges from nearly completely black, to a light creamy color, passing through really gorgeous shades of green and brown,” she says. “The Latin name Hyla versicolor means they change color, and in our experiment, we asked whether they changed color based on ambient temperature, background color, or both.”

They discovered that the arboreal dwellers are darkest on darker backgrounds and at colder temperatures, which means they sense, process, and appropriately respond to their environments.

So the clever frogs—native to the eastern United States—use color-change to better match their background. But why? Ge learned that “cryptic coloration” could be an adaptation to escape being spotted by visually hunting predators like birds. It could also be a mode to stay warm, capturing more solar energy at lower temperatures.

“Color is something I take in, take note of, gather data about, and remain attentive to just by looking,” says Ge. “At least to the human eye, tree frogs on trees or lichen are extremely well-camouflaged, which is especially important when it’s cold and the frogs can’t escape predators very quickly—or at all.” —KC