Physicist Scott Waitukaitis receives an NWO Veni grant to research the Leidenfrost effect for squishy materials. This effect is well-known for dancing water droplets in a frying pan.
Have you ever spilled water on a hot frying pan? You will see the water droplets do a funny dance, floating around on a thin layer of vapor. This is known as the Leidenfrost effect. And as silly as this effect may seem, it is used in serious applications. It is for example essential in nuclear reactors, where the Leidenfrost effect makes sure that the cooling water doesn’t directly touch the smoldering hot nuclear fuel rod. In case of direct contact, the water would immediately vaporize in a giant explosion.
Leiden physicist Scott Waitukaitis is interested in the fundamental science behind this effect, especially for squishy materials. NWO has awarded him a Veni grant to perform experimental research on the subject. 'We all know that water floats on a hot surface, and the same goes for stiff solids like dry ice,’ he says. ‘But squishy materials bounce up and down (see video below, edit.). No-one has studied this phenomenon and with this Veni grant I’m going to conduct experiments using high-speed cameras to look at the height of the bounces, the temperature dependence, the sounds, the amount of water is vaporized per bounce, etcetera.’
In the video below you see hydrogel spheres which are fully soaked with water. Waitukaitis is going to develop formulas to describe the exact behavior of the balls.