There are limitations to studying carbon nanotubes (CNTs) particular as it is very difficult to get an insider view. That could change thanks to work by Nadya Mason and colleagues at the University of Illinois at Urbana-Champaign and Norman Birge at Michigan State University. They have developed a technique to map out changes in conductance through a CNT quantum dot. Superconducting tunneling spectroscopy allows the team to see what is happening inside the CNT rather than merely at its contacts. The approach could open up studies into CNT transistors and possibly even quantum computing devices.