Glassblowing is a glassforming technique that involves inflating molten glass into a bubble, or parison, with the aid of a blowpipe, or blow tube. It was invented in approximately 50 BC by the Phoenicians and hasn't changed hugely since then.
Dale Chihuly, a glassblower makes incredible glass sculptures. Some of his work was exhibited in the W.W. Seymour Botanical Conservatory of Tacoma, Washington.
Glass blowing isn’t an easy job as you need to deal with the temperatures up to 2400 degrees. Glass is a mixture of limestone, sand, potash and soda ash heated to 2,400 degrees. You need a blow pipe to begin the process. This is dipped into the molten glass just as you dip a honey gatherer into honey. Then the glass at the end of the tube is rolled on to the marver, simply a big flat piece of steel. In the olden days it used to be made of marble.
Glassblowing involves three furnaces. The first, which contains a crucible of molten glass, is simply referred to as the furnace. The second is called the glory hole, and is used to reheat a piece in between steps of working with it. The final furnace is called the lehr or annealer, and is used to slowly cool the glass, over a period of a few hours to a few days, depending on the size of the pieces. This keeps the glass from cracking due to thermal stress. Historically, all three furnaces were contained in one, with a set of progressively cooler chambers for each of the three purposes. Many glassblowing studios in Mexico and South America still employ this method. [Via]

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