“Second sound is the hallmark of superfluidity, but in ultracold gases so far you could only see it in this faint reflection ...

But in some exotic materials, heat doesn’t just spread; it sloshes back and forth like a wave. This bizarre phenomenon, known as “second sound”, has intrigued scientists for decades.

Forms of energy are just different types of energy such as heat, light, sound, kinetic and chemical. Energy resources are stores of a particular type of energy. Examples of energy resources ...