Different materials respond in unique ways when stressed over time. Two key ways to understand this are through creep and stress relaxation. Let’s break it down by material type.

1. Metals:

   • At high temperatures, metals can stretch a lot, sometimes more than a thousandth of an inch every second.
   • If metal is under pressure for a long time, like 1000 hours, it can change shape significantly.

2. Polymers (like plastic):

   • With constant pressure, polymers can stretch between 1% to 10% in just a few hours.
   • Over hours or days, the stress they feel can drop by about 30%.

3. Ceramics (think pottery or tiles):

   • Ceramics usually don't stretch as much, with very slow creeping around a billionth of an inch every second.
   • However, when under long-lasting pressure, they can become weaker and may break more easily.

Knowing how these materials behave is really important. It helps engineers predict how they will perform in real-world situations.