On Mon, 16 Jan 2006 14:48:59 GMT, "Blueyonder"
wrote:

The only evacuated tube commonplace in homes today is the TV tube, and look
at how thick the glass is on the from of that to withstand the pressure.

TV tubes illustrate how it's easy to resist the presure, but it's the
force (pressure over an area) that causes the trouble. The big flat
screen is thick, but the small neck round the back is thin. the pressure
is the same, but only when it's a large flat area is there a problem in
supporting it.

Some houses may also have vacuum solar collector tubes. These are thin
glass and properly evacuated, but because they're only a few inches
across they're strong enough. One reason why a practical tube collector
can be evacuated and is thus more efficient than a flat plate - which is
impractical to evacuate.