The ruined school is not what it seems to be. You don't have access inside the buildings, only to a fragment of ruins. The most important thing is what the school hides underground - the Vault 75 (the location's name will change to it after uncovering the vault). It is a settlement of many mercenaries.
Location related to the Vault 75 quest which is activated after entering inside and is about exploring the whole location (more specifically, about reaching the overseer's room).
Science bobblehead can be found in laboratory.
You can open a hidden door by using the terminal in overseer's room. Behind it you will find Grognak the Barbarian magazine.