Frances Arnold

Imagine teaching tiny helpers to become super helpers—just like training a team to win a game. That’s what Frances Arnold did with molecules! Frances Arnold (born 1956) is an American scientist and engineer working in the late 20th and 21st centuries. She invented "directed evolution," a lab trick that improves enzymes (tiny protein helpers). Her work earned the Nobel Prize in Chemistry in 2018.

Directed evolution is like making many slightly different toy robots, testing which ones do the job best, keeping the winners, and repeating that to get super performers. Frances makes small changes to genes that build enzymes, looks for the best versions, and repeats the process. This helps scientists 'train' enzymes to work faster, more precisely, or in new places.

Her idea changed how people make medicines and materials and helped create cleaner ways to do chemistry. Frances is a professor at Caltech and a role model for kids who love solving puzzles. Her work shows how tiny changes and patient testing can lead to big benefits for people and the planet. What tiny helper would you like to teach?