For years, scientists have been working on the development of a Harry Potter type of invisibility cloak. Now, they are one step closer to realizing what would be a stunning scientific achievement. However, there is just one minor problem: it only works underwater. The video below is a brief demonstration of the principles of "photothermal deflection", the effect of cloaking which is caused by the rapid heating of carbon nanotubes. More on this story can be found here.