Wand

A wand is a tool used by wizards and witches to channel magical powers. Most spells are done with the aid of wands. It is possible to do magic without a wand, but is very difficult and requires much concentration and power. Only advanced wizards can perform magic without the use of wands.

Materials
Generally, wands are long, thin rods of wood with a magical substance embedded into their core. Some of the woods used are Cherry, Hawthorn, Holly, Hornbeam, Mahogany, Maple, Oak, Rosewood, Willow and Yew. Although in the official Warner Bros. website Cedar is also mentioned as well as Ash. The cores that have been documented so far are Phoenix feather, Dragon heartstring, Veela hair, and Unicorn hair. Another important characteristic of a wand is its length. On the official website in Ollivanders Wand Shop the lengths range from 7 inches to 13 inches but Voldemort and Ron Weasleys are 13 1/2 and 14 respectively Rubeus Hagrid 16 and 1/2. J.K. Rowling used a Celtic calendar to assign certain types of woods to Ron Weasley, Hermione Granger, and Harry Potter based on their birthdates.

Wand and Wizard
In almost all documented cases, the wand chooses its wizard. This is due to the unique character of each wand, which must match that of the wizard, as the wizard may not be able to perform magic if his and his wand's characters conflict. When trying out different wands, an aspiring wizard may cause some damage when he encounters wands that don't get along with him.

A popular but unconfirmed theory suggests that the wand's length is directly proportional to the wizard's height: the longer the wand, the taller the wizard, and the shorter the wand, the shorter the wizard. Examples of this have been found, as in Dolores Umbridge's short wand, and Ron Weasley's long one.

Examples of damage caused by "mismatched" wands are in the Harry Potter and the Philosopher's Stone movie, where wand boxes flew off of shelves and banged into walls when Harry Potter waved two wands. In the Philosopher's Stone book, he tried out many wands before he found the one that he wanted. Apparently, a warm feeling is felt when the wizard (or witch) chooses the right wand, and the wand sometimes emits a few sparks or does some similar small sign of magic.

Some known wands:

Makers
There are many makers of wands, but the best known, and most experienced in Britain is Ollivander's. The wandmaking establishment has been making wands since 382 BC and is located in Diagon Alley, London. Regretfully, Mr. Ollivander was missing from the summer of 1996[HP6], until he was discovered by the trio and rescued by the house-elf Dobby in Harry's seventh year. His disappearance was a kidnapping by Death Eaters. Ollivander provided Harry with information about the Elder Wand and about the passing of wand ownership.

Another notable wand maker is Gregorovitch, who made the wand of Viktor Krum.