Her performance has drawn a half-million views so far on YouTube.
The 23-year-old Michigan State University graduate and science writer raps about the Large Hadron Collider, the groundbreaking particle accelerator that has been built in a 17-mile circular tunnel at the CERN laboratory near Geneva, Switzerland.
McAlpine raps that when the collider goes into operation on Sept. 10, "the things that it discovers will rock you in the head."
The $3.8 billion machine will collide two beams of protons moving at close to the speed of light so scientists can see what particles appear in the resulting debris.
"Rap and physics are culturally miles apart," McAlpine, a science writer at CERN, wrote to the Lansing State Journal in an e-mail last week, "and I find it amusing to try and throw them together."
Others, including physicists, also find it amusing.
"We love the rap, and the science is spot on," said CERN spokesman James Gillies.
McAlpine received permission to film herself and friends dancing in the caverns and tunnels where the experiments will take place.
"I have to confess that I was skeptical when Katie said she wanted to do this, but when I saw her previous science rapping and the lyrics, I was convinced," Gillies said. "I think you'll find pretty close to unanimity among physicists that it's great."
McAlpine honed her physics rapping skills at Michigan State's National Superconducting Cyclotron Laboratory, where she was part of a student research program two years ago.