NEBOSH Practice Test

What is thermal shock in materials?

1. Slow degradation over time

2. Cracking from rapid temperature change

3. Spontaneous combustion

4. Brittle failure at low temperatures

The correct answer is: Cracking from rapid temperature change

Thermal shock refers to the sudden and severe stress that materials experience when they undergo rapid changes in temperature. This condition can lead to cracking or even catastrophic failure of the material. When a material, such as glass or metal, is subjected to a rapid temperature increase or decrease, different parts of the material expand or contract at different rates. This uneven thermal expansion or contraction generates internal stresses that can exceed the material's strength, resulting in cracks or breaks. Brittle materials are particularly susceptible to thermal shock because they cannot absorb the energy of these stresses effectively. The phenomenon is common in various applications, such as in cookware subjected to direct heat or in industrial ceramics exposed to sudden temperature shifts. Understanding thermal shock is crucial in material selection and engineering design to avoid unexpected failures in structures or components subjected to thermal cycling.