Short answers, pulled from the story.
Modern scholars trace the roots of Passover to ancient apotropaic rituals that predate the biblical Exodus narrative. These early rites were designed to protect family homes from demonic forces using the blood of a slaughtered sheep daubed on doorframes with hyssop.
In 2025, 15 Nisan coincided with Sunday, April 13, meaning Pesach started at sundown on Saturday, April 12. The Rabbinical Jewish calendar aligns with the solar calendar so that 15 Nisan always coincides with Sunday, Tuesday, Thursday, or Saturday.
Leaven in Hebrew chametz is made from one of five types of grains combined with water and left standing for more than eighteen minutes. The consumption, keeping, and owning of chametz is forbidden during Passover under Halakha.
Karaites use a different calendar relying on visual identification of ripe barley before determining the date. Since the 4th century, intercalation has been fixed mathematically according to the Metonic cycle instead of relying on witness testimony for Rabbinic dates.
Afikoman must be consumed during twelfth part Tzafun substituting for eating sacrifice at end of Seder meal. Many families use afikoman device keeping children awake alert throughout proceedings by hiding piece offering reward its return.