Metal's capacity to tolerate heat is one of its most essential properties. All metals, however, may be heated to the point of deterioration. Metals are prone to overheating and burning when exposed to high temperatures. As metal heats up, it expands thermally, causing it to wrinkle or even break. Also, certain metals such as iron and steel lose their strength when heated past a certain point. If you were to put a metal object in water and remove it after some time, it would be cold and stiff. This is because metals become hard when they are cooled down too much. They can only be softened by heating them up again. Metal objects that get hot enough to melt sand or soften wood are called "red-hot". People have been heating metal for cooking since at least 600 B.C. But people started buying metal pots and pans about 100 years ago, so if you're looking for new dishes, don't worry about how hot metal gets. The best way to avoid damaging your metal cookware is to follow some simple rules: never leave anything hot in the kitchen (including metal utensils), and always wash your hands after handling hot items. If you do happen to burn yourself, apply cool water immediately.