From what I understand, the word midnight is usually interpreted incorrectly. Midnight is written as 12am which would imply that it's in the morning. Therefore, it should be at the start of the day. On the other hand, both Dictionary.com and the Oxford Dictionary define it as twelve o'clock at night.
James Prescott Joule. The English physicist James Prescott Joule (1818-1889) proved that mechanical and thermal energies are interconvertible on a fixed basis, and thus he established the great principle of conservation of energy.
Getting to know the Joule (J), an energy unit. The idea: Developing a familiarity with the Joule will help ground your further work with energy. Many sites provide definitions of joules for you, and many others describe equations in which energy is a variable.