This is cork -- the actual tree bark from which corks are made.

Cork is from the coak oak tree.

I've always known that cork was an actual tree product, but it was really interesting to actually handle a piece of cork oak (I bought some as a souvenier, too). The back is extremely light, the piece seen below was about 2 feet long, and about 3 inches thick, but it only weighted, maybe half a kg.


When we think of cork, we only think about bottles of champagne or wine. However, cork is actually used in lots of other places -- including the space shuttle.

It turns out cork is extremely fire resistent, and is one of the best fire resistent insulators (better than most synthetics). Also, its resilency to being pressed (elasticity) is also very high (again, better than most, if not all, synthetics). As such, cork has many uses in technology.

For example, cork is used to back the glass tiles in the space shuttle, as an extra layer of heat protection. Cork is also used in bridges, and roads, in expansion joints (as it helps to maintain the integrity of the bridge).

Astounding!