A new type of pressure sensor, pioneered by scientists at the University of California, Riverside, uses changes in color to show how much force a surface “feels.”

According to a release from UCR, the new sensor consists of a polymer film embedded with strings of gold nanoparticles. The film deforms when pressed, stretching the nanoparticles apart. “This increased separation alters the way the nanoparticles interact with light,” said Yadong Yin, an associate professor of chemistry, whose lab led the research.

“When linked together, the gold nanoparticles originally appear blue,” he also said. “But they gradually change to red with increasing pressure as the nanoparticles start disassembling. This easily and visually helps us figure out how much pressure has been applied.”