have you ever noticed how sometimes older and very powerful wizards (I know Dumbledore does this) can just wave their arm or flick their wand without saying anything and perform a spell? Like if there's a mess on the floor or something they just flick their wand at it and suddenly the floor is sparkling clean. I've never quite understood how that works.
I think this is partly to do with power and partly to do with subconcious will/action.
Dumbledore can do several things with out saying the spell or without a wand because he is very powerful and has great control over his abilities. Young wizards can do magic accidentally. But when learning to control their ability they use wands as a kind of focal point for their power. I've always thought that wands weren't
necessary for magic but that they were more like a conductor for magic. Wands
help but they aren't required.
If a wizard, like Dumbledore, wanted to do magic but didn't have a wand they can but it is harder to control and may possibly wear them out more than if they had a wand.
Now, on the other hand Mrs. Weasley can casually wave her wand at a mess on the table and not say an incantation because this is something that she probably does four or five times a day and in her minds eye she nows exactly what she wants to happen and therefore doesn't need the assistance of words. It is like a driving to work. I drive here everyday and more often than not find myself here without a clear memory of turning down a specific road, I sometimes find myself here on a day off because while on my way somewhere near by I unconciously turned down this road instead of the other.
Does that make sence
These are my opinions. Questions, coments, and proofs that they are right or wrong are as always very welcome