Kids through the ages have wondered how the coloured bits of glass got inside their marbles. In this film we reveal the secret, and see how the skill and imagination of the craftsmen in the glass blowing workshop can turn simple sandy granules into beautiful orbs of patterned glass.
Glass is a fluid, even at room temperature - it just flows very, very slowly. So you can amaze your kids by telling them that after ten thousand years or so, a marble such as the one we see being made in the film would become a glass puddle!
The study of marble making is the perfect way to understand how heat is used to speed up flow-rate, or reduce viscosity, making the glass malleable for the marble-maker. It also demonstrates the intense heat needed to melt and shape the glass: first in the gas furnace that turns sandy granules into a liquid; then in 'glory holes' - the warming ovens that glass blowers use to keep the glass on their rods nice and soft.
There are many technical terms to learn in this film, such as 'annealing', 'gob', and 'punty'; but with a superb music track and fascinating visuals, it - like all our Magic of Making films - can be enjoyed without listening to a word!
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This film is also available on the DVD:
'The Magic of Making - Volume 1'.