: an isomer that is a stereoisomer of a compound having two or more chiral centers and that is not a mirror image of another stereoisomer of the same compound â
A compact disc is a deceptively simple looking device considering the technology required to make it. 1  CDs consist of three layers of materials: 2  A base layer made of a polycarbonate plastic. 3  A thin layer of aluminum coating over the polycarbonate plastic. 4  A clear protective acrylic coating over the aluminum layer.
2) Quality Wheels. Proper skateboard wheels are made out of polyurethane with minimal additives. Toy skateboard wheels can be made of plastic or a low quality poly mix which leads to poor performance in the best case and even outright dangerous situations with cracked wheels in the worst case.