Wandlore is a magical thing in Harry Potter, and we still have so many questions about it...
The wands in Harry Potter are essential, allegedly, in the production of spells (or, to be more specific, the streamlining of magical energy exiting the body.) They are universally constructed from a wooden shell that envelops a powerful core, but these two items can be combined in innumerable ways to design unique wands.
Not everyone uses them, however, for instance, House-elves possess their own brand of magic that can even outperform spells cast by humans. This raises so many questions about how these items actually work.
It looks like wands originate from Europe, with the two most important wandmakers being the Ollivander family (est. 382 BCE after the patriarch arrived in Great Britain along with the Romans), and Mykew Gregorovitch, whose ancestry is unknown but is quite an important figure in Eastern Europe.
According to the extended canon, there are a few others mentioned, in ambiguous fashion, but no more information is provided about any others. This fact certainly does require a fair bit of elaboration.
One of the most iconic quotes in the story, oft-repeated, is "the wand chooses the wizard", but the reasons behind this are still quite murky. Ollivander implies that the whole concept of wandlore is "mysterious", which is ironic because of his legacy in studying and constructing wands.
It could be due to an affinity that the magic-user has towards the type of wood employed, or, in Harry's case, the core, but it is likely to be a combination of both factors (or neither, because wands just don't follow normal rules, it seems.)
Sure, there is no real possibility that a witch would be fighting in outer space, but Harry casts spells to great effect whilst underwater, during the second round of the Triwizard Tournament, in order to dispel a Grindylow attack.
Interestingly, the effect of Relashio was completely disparate from its use on land in that it spurted forth boiling water rather than the expected shower of sparks. Does this mean that all spells would have a unique effect underwater? What about under different atmospheric pressures?
The fact that European and American magic-users employ wands to direct their spells is well known, but what about communities across the world — do witches in India, sorcerers in China, warlocks in aboriginal Australia also use a wand or any other kind of channeling device?
Are there specific varieties of wands depending on the country, for instance, is there a distinction between French and German wandmaking? The historical description given to wand usage is sorely lacking in international content.
As far as tradition is concerned, wands are made of wood, but the potential variety available is rather vast. In addition to the popular trees depicted in the stories, Maple, Redwood, Pear, Cypress, Aspen, Blackthorn and countless others are also included in the production process.
Similarly, the cores can be bizarre, like Wampus cat hair, Basilisk horn, Troll whiskers, and so on. More importantly, is it possible, say, to incorporate a magical core within the limb bones, thereby converting the arm itself into a wand?
Very often the spells that emerge from a wand behave as if they are living, the Patronus charm being a prime example, but what about the instruments themselves? Since the wand decides who it wants to belong to, there is an implication that it possesses at least a limited form of consciousness that allows in processing this decision.
Although they are unable to actually talk to their witch/wizard, do they have the capacity to use a different type of communication (aside from the warm glow and random sparks that burst out when someone picks a perfectly matched wand)?
Ollivander has claimed that the size of the wand depends on the size of the witch, for example, Hagrid's 16-inch wand compared with Professor McGonagall's which is only 9.5 inches in length. But this has shown to be inaccurate, especially in the case of Ronald Weasley, whose second wand is a whopping 14 inches.
Another aspect that doesn't have enough clarification is flexibility, which is described in terms like "supple", "bendy", "springy", and so on. Does this have any role to play in spellcasting?
According to tradition, the Elder Wand was created as a kind of deathstick, in the sense that anyone who wielded it tended to use it to kill other magic users. Obviously it was not created by Death (or maybe it was, who even knows anymore?), but it certainly has a potential far superior to every other wand in the world.
Its greatest accomplishment, aside from Dumbledore's victory against Voldemort in the Battle of the Ministry Atrium, is when Harry uses it to fix his original wand, something that was believed to be totally impossible. Is it to do with the Elder wood or the Thestral-hair core?
The films don't make this fact very clear, but the books aren't that much better: wands apparently flip allegiances at the drop of a hat; all that's needed is for the old master to be "defeated" by the new one. But what does this actually entail?
Harry claimed the Elder wand by literally wrestling Draco Malfoy's wand out of his grasp, physically and without magic, so are spells not even necessary to steal another wand? Also, when friendly sparring matches happen, like during the Dumbledore's Army practice sessions, does accidentally stupefying someone mean the attacker gets their wand?
The entire premise of Hogwarts is based on wands, with students spending their seven years trying to master various patterns and flourishes. But there is such a thing as wandless magic, although this form is only seen being used by immensely powerful characters like Dumbledore and Voldemort.
Still, it feels like a wand is a crutch, like training wheels for wizards who haven't yet learned to wield magic from their fingertips. Imagine how much more epic each spell would look this way!
