This tub of plasticine (see photo below) has been sitting in a box at the back of my study. I don’t think it has been subjected to any particularly extreme environmental events, yet it looks like it is covered in white crystals. Any ideas how this has happened?
• Plasticine is a mixture of calcium salts – mostly calcium carbonate – petroleum jelly and aliphatic acids – mainly stearic acid. , meaning that it is a hydrocarbon chain with a carboxyl group at one end. Rather than having the consistency of a fat, it forms crystals. Most fatty…
