Surprising video of a metallic pencil sharpener igniting and burning up like a bright white blinding flare.
The sharpener is actually made of magnesium metal, a close relative of aluminium. When it is heated by the blow torch, it first starts to melt. With a little bit of extra heat, a small bit of the sharpener ignites. The flame quickly spreads and soon the flame is so bright that the filmer stops recording and moves his iPhone camera to safety.
The sharpener continues to burn for another 30 seconds or so, leaving just a white powder of magnesium oxide behind. Technically the metal doesn't burn, but rather rapidly corrodes.
This activity clearly demonstrates how much energy is stored in magnesium (similarly aluminium). This is the amount of energy required to change magnesium oxide to magnesium, which is why we should recycle metals such as aluminium. Aluminium is sometimes characterised as solid energy.
Video taken by Jacob Strickling creator of the popular YouTube Channel 'Make Science Fun'