- Palm Sunday (Wikipedia)
Palm Sunday is the Christian moveable feast that falls on the Sunday before Easter. The feast commemorates Christ’s triumphal entry into Jerusalem, an event mentioned in each of the four canonical Gospels. Its name originates from the palm branches waved by the crowd to greet and honor Jesus Christ as he entered the city. Palm Sunday marks the first day of Holy Week; in Western Christianity, this is the beginning of the last week of the solemn season of Lent, preceding Eastertide, while in Eastern Christianity, Holy Week commences after the conclusion of Great Lent.
- Bohr model (Wikipedia)
In atomic physics, the Bohr model or Rutherford–Bohr model is an obsolete model of the atom, presented by Niels Bohr and Ernest Rutherford in 1913. It consists of a small, dense nucleus surrounded by orbiting electrons. It is analogous to the structure of the Solar System, but with attraction provided by electrostatic force rather than gravity, and with the electron energies quantized (assuming only discrete values).