Published on 29 Apr 2014 This talk was given at a local TEDx event, produced independently of the TED Conferences. Typically our response to fire is Danger! and Devastation! But in this talk, Claire Belcher describes how fire also does positive things for our planet, including regulating the amount of oxygen in the atmosphere. […]
Obsidian tools
Obsidian is a volcanic extrusive rock with a glassy texture that is very hard and dense. The volcanic glass is usually black in colour, but it can also be dark green and brown. In rare cases trace elements of mineral crystals can cause obsidian to reflect light in various colours, or even the colour spectrum […]