Talk of the Nation

Speaking in South Korea, President Barack Obama said that the U.S. can further reduce its nuclear arsenal, while maintaining its security. Some insist that a credible nuclear deterrent requires a sizeable stockpile of weapons.

Florida's "Stand Your Ground" law faces increased scrutiny after the death of Trayvon Martin, the unarmed teen who was shot and killed by neighborhood watch volunteer George Zimmerman. State Rep. Dennis Baxley (R-Fla.) co-sponsored the law and says it does not appear to be applicable to that case.

Transcript

NEAL CONAN, HOST:

This is TALK OF THE NATION. I'm Neal Conan.

As part of an NIH-funded project, Bradley Smith, associate dean for creative work, research and graduate education at the University of Michigan, posted a collection of optical images and MRI scans of human embryos to the web. Intended for a clinical audience, Smith talks about the unexpected response he got from the public.

At age 11, actor Alan Alda asked his teacher what a flame was. He received a confusing answer: "oxidation." In the spirit of better communicating science, he's created the "Flame Challenge," a contest in which scientists do their best to define a flame. Eleven-year-olds from around the world will judge the entries.