Why was El Reno, Oklahoma tornado downgraded to EF-3?

The tornado that struck El Reno, Oklahoma on May 31, 2013 has been reclassified from an EF-5 to a EF-3 tornado. Why?

Understanding the radioactive legacy of Chernobyl and Fukushima

Scientists fear not enough is being done to study long-term effects of radioactive contamination from the nuclear disasters at Chernobyl and Fukushima Daiichi.

Scientists create mini human brains in lab

Researchers have developed complex human brain tissue in a 3-D culture system that allows pluripotent stem cells to develop into cerebral organoids - or "mini brains" - that consist of several discrete brain regions.

Video: 4 minutes of 6-second science

Compilation from GE's #6SecondScienceFair. Go from "wow!" to "huh?" and back again.

Snapping turtles finding refuge in urban areas

Snapping turtles are surviving in urban areas as their natural habitats are being polluted or developed for construction projects.

First human brain-to-brain interface

Brain signal sent via the Internet from one researcher controls the hand motions of a fellow researcher.

More photos and update on California’s Rim Fire

As of August 28, the fire is 20% contained. Thousands of firefighters are still battling the blaze, which has burned 184,481 acres near Yosemite National Park.

Authenticating the world’s most expensive coffee

Coffee cherries eaten by palm civets create the world's most expensive coffee. But blatant forgeries use beans that have never seen a civet's insides.

Monarch butterfly habitat in Mexican forests at 20-year low

Climate change and illegal logging in Mexican forests, where the monarchs spend the winter, may be contributing the decline of monarch butterflies.

More people, more air pollution

But the population-pollution relationship is not the same everywhere.