How does a fan use electrical energy? The fan turns electrical energy into energy of motion.
The fan turns wind energy into electrical energy.
The blades of the fan spin and produce electrical energy.
The fan turns electrical energy into light and heat energy.

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later