Consumer Reports has found that modern Pyrex glassware is less resistant to thermal shock than Pyrex which was made years ago. This is due to changes in the type of glass used to make Pyrex.

This mundane example reflects the problems engineers face when trying to recreate old systems. Components and materials that were used in the original design may no longer be available, and if they are still being manufactured, the new items may not be functionally identical to the original. That’s why it isn’t feasible to rebuild the Saturn V today, as some nostalgic space buffs have suggested. It’s not because NASA has lost the blueprints – that’s an urban legend – but because the supply chain for critical components no longer exists.

[youtube=http://www.youtube.com/watch?v=UyhdMa1ikKM&w=700]