The amount of sodium chloride in the original mixture can be determined indirectly by subtracting the masses of ammonium chloride and sand from the initial mass of the powdered mixture. calculate the percent difference between the results from the two methods using the following equation: % difference = |(measured mass) − (mass by subtraction)| / (mass by subtraction) × 100%

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