Season 4
Episodes
1 Forest Fires, Car Exhaust, Space Station Apr 11, 2007 2 Family Car, Titanium, Letter Apr 11, 2007 3 Nuclear Sub, Crash Test Dummies, Fruit and Vegetables Apr 18, 2007 4 Land Mines, Air Boats, Warehouses Apr 18, 2007 5 Black Boxes, Steam Turbine, Racing Car Apr 25, 2007 6 Jet Engine, Weapons, Telescope Apr 25, 2007