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"Prince Rupert´s Drop"

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Product-ID: 49-0000

24,95 EUR

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Please note: The Prince Rupert's Drop cannot be delivered to the USA and Canada!

Product description

Place the toughened saftey-glass and the Prince Rupert´s Drop ready

Toughened safety-glass is a plate glas with special characteristics. If damaged, it forms a net of small, mostly blunt-edge glass granules that reduce the risk of injury. Therefore it is especially used in side and back windows of cars or glass doors.

“Prince Rupert´s Drop”, in Germany also known as "Batavische Tropfen" or “Bologneser Tränen”. These small metastable glass drops are a physical curiosity that even as far back as in the 17th century kept scientists busy.
The “glass drops” are quite stable on the thick end but will burst into a thousand pieces if you break the apex. The high tensions within the drop result from the fast cooling-off process. Hot melted glass that is cooled off quickly, first gets cold and solid on the surface and surrounds the hot and still liquid glass on the inside. The latter cools off slowly and continously from the outside to the inside. As liquid glass concentrates more than solid glass while cooling off, a certain mechanical pressure emerges. A piece of glass that is cooled off too quickly has the characteristics of a small bomb, even though instead of exploding it implodes. Solid glass is quite restistant to compressive stress that prevails inside the glass (approx. 100 kg / mm2) and to tensile stress on the surface (approx. 5 kg / mm2) and therefore is not likely to break. As a result, a piece of glass that was cooled off too quickly is always close to bursting into a thousand parts but nevertheless it is possible to stand on or put some heavy weight on it. But as soon as the surface is scarified or cracked the fragile balance is disturbed and it will atomize into tiny splinters.

This process is used, among others, as well for the production of toughened safety-glass. A special treatment ensures that the glass, if damaged, forms the characteristic net of small, mostly blunt-edge glass granules that reduce the risk of injury.

“An experiment is a question which science poses to Nature, and a measurement is the recording of Nature's answer.” Max Planck

This is how you do it (Warning! Use protective goggles and protective gloves during the whole experiment!):

Place the toughened saftey-glass and the Prince Rupert´s Drop ready

Insert carefully the apex of the drop into the whole in the cap of the saftey-glass. (Warning! Use protective goggles during the whole experiment!)

Screw the cap on.

Now use a caliper to break off the apex of the drop. (Warning! Use protective gloves during the whole experiment!)

The Prince Rupert´s Drop will implode with a big bang and atomize into tiny splinters.

Find two very interesting videos attached here:

Prince Rupert's Drop (wmv)
http://www.youtube.com/watch?v=8-GOwtikSO0&feature=related

http://www.youtube.com/watch?v=og8NTWSWOWc

You will also find more detailed information here

Included in delivery:

The Experimental set “Prince Rupert´s Drop” includes:

Glass drops: 5 pieces
Toughened safety-glass: 1 piece

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