This is a demonstration of how nitrating cotton can affect its chemical properties.
If you have ever burned cotton wool, you will know it burns readily but slowly, and will leave a mess of carbon (unburned material) behind. The reason for this mess is that the oxygen in the air has to meet the cellulose (and other) molecules. The cellulose molecules have to break into their components (carbon, hydrogen and oxygen) and combine to form carbon dioxide and water. If oxygen is mainly coming from the air (and the small amount in the molecules) then it is just not able to get to there in time as it is burning. Hence a lot of the carbon goes unreacted, and the reactions that do occur are not very quick.
Adding nitrate groups to the cellulose molecules in the cotton wool actually provides a lot of oxygen atoms within the structure (there are 3 oxygen atoms in every nitrate group). Now, when it is set alight, the oxygen and the carbon / hydrogen atoms can meet very quickly because they are already practically side-by-side and then react incredibly fast. Also, note that there is no residue of black powder or unburned nitrated cotton left - the carbon and hydrogen (and also nitrogen) atoms completely reacted with the oxygen atoms.
Credit: David Bonner for recording the footage and putting the video together.
