The power of cool: Whatever became of Starlite? : So Lewis decided to take a closer look at Starlite with a scanning electron microscope. It was then that he noticed the surface had subtly altered in response to the heat. In particular, he saw that a network of small voids, each one between 2 and 5 micrometres wide, had formed. "I thought 'This is it! That's why it works'," he says.
Lewis realised that these voids transform Starlite's properties. They act like air bubbles in a foam, providing insulation and reducing the material's thermal conductivity by at least an order of magnitude compared to fresh Starlite. But crucially, they are small enough not to disrupt the material's ability to reflect and emit heat from its surface.