It is Mark’s birthday. He is having a party. He is given a birthday card. There is a birthday cake with icing on it. There are candles on the cake. Afterwards, they all eat jelly. All these materials are weak. But which one of these materials is the weakest?

You know that some materials are hard and others are soft. Some break easily but others do not. Some materials are weak and some are strong. Wool is soft, but if you pull it, it is quite strong. A glass vase is solid. It is hard to the touch. But it can break easily - it is weak if it is dropped.