Ductility is when a object can get past the yield point and forms a neck After that it breaks. Brittleness is the exact opposite it can’t get past the yield point and then it breaks. At different temperatures Brittleness and ductility swap so when an item has ductility in cold weather it turns into an item with brittleness. Now when an item with brittleness like glass gets warmed up it has ductility. The Titanic we all know it hit an iceberg and sank but it had sank because of the weather was so cold it turned the item which was used to make it was turn in to an item with brittleness.