A Day of Reactions with Dr. Woolard

Magnesium Oxide

This is a teaspoonful of magnesium powder that was placed in a bunsen burner. The bright white is the magnesium metal reacting with oxygen to form magnesium oxide (MgO).

Magnesium Ribbon

Essentially, this is the same process, except that the magnesium metal is in a strip, or ribbon. Granules have more surface area than big pieces, so there is less surface area on the ribbon, and therefore a slower reaction takes place with a less blinding light.

Close-up of Sodium

This is a piece of sodium metal, which is about the same size as your pinky-finger’s nail. The layer on top is an oxide layer. (Na₂O)

Chromium

Shown is a needle with chromium metal granules on it. Chromium reacts much slower than the other elements mentioned above, so the flame is significantly dimmer. Again, it is reacting with oxygen and producing chromium oxide (CrO and Cr₂O₃).

Copper

This last one is my favourite; copper is used very often commercially, as it is cheap, lightweight and a good conductor, although most people realize that it actually emits a blue-green flame, which is nature’s rarest colour. Here you see copper changing oxidation states (valency) from copper I oxide (Cu2O) – the standard red-brown substance we know – to copper II oxide (CuO) – a black powder – which actually turns blue in the heat!

Matt