Using a fast-pulsing laser, physicists have recorded the first moments of electrical resistance, the friction that generates heat as electricity travels through circuits.

Physicists knew electrical resistance didn’t kick in the moment a voltage was applied. Electrons experience some freedom before slowing to a crawl and scattering. What wasn’t certain was how quickly they make that transition (illustrated in the animation above, with electrons in blue, “electron holes” left by departing electrons in red, and voltage signified by the green arrow).

Struggling to understand a Biological Concept? Watch our growing library of Biology videos and you will see how easy it is to take a concept and make it fun. People all over the world have been using these videos to make their C's into A's. Check them out, and have fun learning.

The reluctance of women to enter STEM fields seems to have deep roots — which often don’t disappear even in the face of success. One of Dr. Klawe’s favorite topics is what she calls The Imposter Syndrome. “Even women who get into MIT, and major in engineering,” she says, “often continue to second guess themselves, worrying that success was a mistake. So the first time they get a B on an exam, they switch to a major in the humanities.  Yet males can get all C’s and think they’re doing great. It’s just normal for males to overestimate their success and for women to worry that they don’t deserve to be where they are. That insecurity often haunts them into their professional lives.”