SQA National 5 Design and Manufacture Practice Exam 2026 – Complete Prep Guide

Polystyrene is a versatile plastic that is commonly used in various applications, particularly in the manufacture of products where lightweight and rigidity are desired. CD cases are a prime example of an item made from polystyrene because it provides a durable, transparent casing that protects the discs while allowing visibility for labeling.

The choice of polystyrene for CD cases also stems from its ability to be easily molded into specific shapes, which is essential for creating tightly fitting and protective enclosures for fragile items like CDs. Furthermore, polystyrene can be produced in varying thicknesses, enabling manufacturers to customize the strength and flexibility of the cases as needed.

In contrast, the other options typically involve materials that are better suited for their specific uses. For instance, automobile parts often require more robust and heat-resistant materials like polypropylene or reinforced plastics. Electrical wiring is made from materials like copper or aluminum combined with insulating coatings to ensure safety and conductivity. Kitchen utensils are usually made from materials that can withstand heat and exposure to food, often involving other plastics or metals instead of polystyrene.