Kevin Delaney leads Jimmy Fallon and Lucy Liu in a series of science experiments on "The Tonight Show Starring Jimmy Fallon" on Nov. 7.

In case you missed it, the Museum of Discovery's Kevin Delaney once again appeared on "The Tonight Show Starring Jimmy Fallon" last week! Delaney, the director of visitor experience at MOD, made his debut on the national television show earlier this year, and was invited back for another round of amazing science experiments.

With "The Tonight Show" host Jimmy Fallon and actress Lucy Liu as his lab assistants, Delaney demonstrates different densities in various gases: He lights floating hydrogen gas bubbles on fire; makes a boat float in mid-air with sulfur hexafluoride; and in the finale, creates a giant cloud with hot water and liquid nitrogen.

Check out the clip below, and learn more about Kevin Delaney in our Q&A here. Watch Delaney's first appearance on "The Tonight Show" here.