colin wrote:
"PeterD" wrote in message
...
On Thu, 01 Feb 2007 12:58:14 GMT, "colin"
wrote:

well normally in order to cuase an explosion you have to have a
combustable
material that burns very quickly,
the force comes from the fact that the burnt material wich is oxidesed
takes
up a great deal more volume
and until it expands is under great pressure. in an empty oven there is
no
combustables.

WEll, almost right... (and your 'normally' does apply, so what you say
is true, but there's more! bg)

All you need is pressure, not a combustable substance.

In the case of the balls that 'exploded' were they to have a 'strong'
outter shell, and a high moisture content inside, the moisture could
easily convert to steam and build up pressure until the outer shell
failed--an explosion... It would not be difficult to build up a
hundred PSI of steam pressure, and that would result in a rather large
'bang'!

aha yes the Boiling liquid expanding vapour explosions didnt think of that
at the time,
but I did think enough to say normally lol,
bit like eggs that explode when you put them in a microwave without first
making a hole in them,
although its not all that exciting.

Colin =^.^=





Once upon a time whilst visiting the in-laws in Germany, my wife
reheated some hard boiled eggs in their shells in the microwave by
placing an egg in a glass tumbler and then a slightly larger one over
the first 'in case they pop'. They were then placed on the table for
'früstück'. A full two minutes later an egg exploded covering not only
us, but the ceiling, drapes and nick nak display shelves with egg. A
frantic clean up campaign started as was had a little over a hour to
restore the dining room to its pristine condition before the
mother-in-law returned. We can laugh about it now, but we never have
told the in-laws about it. One day when my father-in-law has to change a
light bulb (long-life of course) he might find a bit of dried egg and
wonder....