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.
joule. 1. A unit of work or energy transfer. One joule is equal to work done by a force of one newton moved about 1 m in the direction of the force. 2. (J) A unit of energy equal to the work done when a force of one newton is applied through a distance of one meter. Used instead of calorie: 1 J = 0.239 cal.