Random Things About The Rules Of Magic In The Wizarding World (15 items)

(#15) It's Impossible To Resurrect People Through Magic

In Deathly Hallows, Harry uses the Resurrection Stone to bring his loved ones to him. The magic of the stone can't bring someone back to life, however, so they aren't truly back. They are echoes or souls of people Harry wants to see, and that's the extent of a person's return to the land of the living.

As it is, no magic can keep death at bay - Voldemort simply delayed the inevitable with the Horcruxes. Studies are ongoing at the Ministry of Magic through the Veil Harry and his friends came across. Nothing conclusive has ever been uncovered and wizards currently have no choice but to either accept their deaths or return as ghosts.
(#7) Dark Wizards Who Attempt The Patronus Charm Will Be Killed By Their Own Wands

Raczidian was a dark wizard who lived in a castle surrounded by dementors and grew to have control over them. His dementors were driven out by a hero known as Illyius through the use of a Patronus charm. Raczidian had never witnessed a Patronus before and considered it a spell of immense power that he wanted to use.

Unfortunately for Raczidian, he learned the hard way that a dark wizard is incapable of casting a Patronus. Raczidian's attempt resulted in his wand sprouting out so many maggots that they covered him entirely until the maggots devoured Raczidian whole.

Raczidian is an example for all dark wizards about the extent of magic they can use, with Voldemort and his Death Eaters also shown to be incapable of casting a Patronus.
(#2) Happy Magical People Can't Become Ghosts

Harry wonders why the Wizarding World isn't filled with ghosts after Sirius's demise. Nearly Headless Nick tells him that Sirius has moved on and won't be coming back. Nick doesn't know why a person doesn't return and, in truth, it comes down to a wizard's personality.

A witch or wizard needs to be in a state of regret or fear to become a ghost - happy people don't fit the requirement. Many have speculated on the possibility of Fred Weasley returning as a ghost, but Fred was a brave person who would have accepted death rather than be saddened by it. Fred even smiles in his last moment, ruling out any possibility of him as a ghost.

Magical people can return to Earth, but those who feel they have lived fulfilling lives won't do so. Characters like Moaning Myrtle and Nearly Headless Nick were sad in their last moments or lived depressing lives and moving on scared them.
(#12) Moving Pictures Need To Be Developed In A Magical Potion For Them To Work

Magical cameras don't exist and the process of creating the standard moving pictures of wizards comes down to the use of potions. A picture from a normal camera that can develop film is needed, which can then be dipped into a magical potion in order to bring the pictures to life.

A Muggle can do the same thing, in theory, as they just need to procure the required potion to make their pictures move, as well. Since wizards don't share the knowledge of this potion, Muggles are stuck with their stationary images for now.
(#8) A Distant Wizarding Ancestor Is Needed For A Muggle-Born To Have Magical Powers

A true Muggle-Born doesn't exist and it's not possible for a person to manifest magical powers without a wizarding relative. People like Hermione are considered Muggle-Borns due to their lack of knowledge of their family tree.

Every person who has magical abilities has had at least one ancestor who was a witch or wizard. Hermione is the first wizarding child born to her family in generations, but she isn't the only magical person in her ancestry. A wizarding relative with a different surname is the most likely scenario for Hermione to become a witch as a member of the Granger family.
(#13) Wizards Are Perfectly Capable Of Doing Magic Without Wands

In The Prisoner of Azakban, Albus Dumbledore points toward Harry as he falls from the sky to immobilize him in midair, which attests to his innate magical ability. While witches and wizards usually use wands in the main Harry Potter series, they don't actually need them and can be trained to do the same magic on their own.

Students at Uagadou, a wizarding school in Africa, are trained to become experts in Transfiguration, Alchemy, and Astronomy. All of their magic is accomplished without the use of wands, as the entire continent of Africa completes their magical needs using natural magic.