Ceramics, unlike metals, cannot alleviate localized tension. The strength of a ceramic is also affected by its grain size. The ceramic becomes weaker as the average grain size increases. For example, a fine powder will not be as strong as a coarse one of the same material. The strength of a ceramic is dependent on how well its particles bond together. The smaller the particle size, the stronger the material. As the particle size grows larger, the material becomes weaker. When making clay pots, it is important to choose an appropriate type of clay. If you use too soft a clay, then when you bake it, the surface will collapse after cooling which makes it less useful for cooking containers. If you use too hard a clay, then it can be difficult to work with and the finished product may not hold its shape well. The type of fuel that is used to fire pottery affects the size of the grains in the clay. If you make bread-moulded pots using wheat flour, then the grains will be very small. In contrast, if you use cake mix for baking, then the grains will be much bigger. Grain size also depends on where in the world you find clays used for pottery.