Temperature plays a big role in how strong or weak materials can be. This is really important when building things that need to stay safe and strong. When materials get hot, they can stretch and change shape without breaking. This is called ductility. It helps structures, like buildings and bridges, absorb energy during things like earthquakes, making them safer.

On the other hand, when materials cool down, they usually become more brittle. This means they can snap or break easily. For example, steel turns brittle when it's very cold. It can break suddenly with hardly any warning. Scientists often use a test called the Charpy impact test to show how tough materials are at different temperatures.

Temperature also changes how the tiny atoms inside materials move. When it’s warm, the atoms shake around a lot. This movement lets the material change shape, which is good. But when it gets cold, the atoms become stiff and don’t move as freely, which can cause the material to break more easily.

Different materials respond to temperature changes in different ways. For example, some plastics, called polymers, get stretchier when they are hot, but they can become brittle when it’s cold enough. Knowing how materials behave with temperature changes is really important when choosing the right materials for construction, especially in places that experience hot and cold weather.

In summary, understanding how temperature affects materials is crucial for engineers. They need to think about these factors to keep buildings and other structures safe and working properly, helping to avoid serious accidents.