On Tuesday, April 23, 2002, at 08:10 PM, John Haumann wrote: > On 4/23/02 at 7:26 PM -0500, Jeremy Derr wrote: > >> On Tuesday, April 23, 2002, at 06:21 PM, [EMAIL PROTECTED] >> wrote: >> >>> There are many opinions on this matter, but starting and shutting down >>> a computer causes it to heat up and cool down. materials expand and >>> contract with temperature differences which can lead to small cracks >>> or >>> breaks and that is all it takes >> >> This is one of the more original explanations I've heard. Have any >> proof? or is this anecdotal? > > You're kidding here, right? The coefficient of thermal expansion for > materials is a fundamental engineering consideration when you build > anything. In general, an increase in temperature causes an increase in > size (there are a few wxceptions -- shrink wrap comes to mind). A > thermostat takes advantage of the phenomena. Two materials, each with a > different expansion coefficient, are bonded together. When the > temperature > changes, one side expands more than the other, and the strip bends > forcibly > toward the side having the lower coefficient to make (or break) an > electrical contact. You can design to allow for or minimize movement, > but > you can't ignore it. > > Leaving the machine on doesn't eliminate thermal changes, but the > temperature swings between "on" and "stand-by" are smaller than between > "on" and "off". Smaller temperature swings = smaller movements.
Oh no, I'm quite aware of the physics behind things expanding (generally) when they heat up. What I mean is, I'm pretty sure there's no proof that repeated reboots cause cracking due to this. Seems to me they tend to use products like silicon and epoxy (and other) resins in computer components, both of which are rather resilient chemicals and don't tend to crack when exposed to repeated expansion and contraction; this is, for instance, why resins are used in the gaps between highway bridge sections. Granted, the specific resins they use in electronics components aren't the flexible rubber-like compounds they use in highway construction, but the principal is the same. -- The iMac List is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | - Epson Stylus Color 580 Printers - new at $69 | & CDRWs on Sale! | SPECIAL LIST PRICES - Apple iMac CDROMs from $79.99, iMac DVD CDROMs from $99.99 3 port USB Hub $14.99, 40GB Hard Drive Upgrades $119 <mailto:[EMAIL PROTECTED]> Support Low End Mac <http://lowendmac.com/lists/support.html> iMac List info: <http://lowendmac.com/imac/list.shtml> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/imac-list%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
