The reason why we need to preheat is because:
To bake bread, because the oven temperature to rise from room temperature to close to 200 degrees (depending on the temperature of different baked products) takes a relatively long time, if the oven is not preheated, the dough in the oven during the process of warming up will continue to ferment the gas production, the dough will be overflowing out of the molds, out of the product will be very large holes, water loss is serious, the surface of the skin is thick and dry cracks, no due to the fluffy and intact shape, the flavor is completely lost. There is no fluffy and intact shape, and the flavor is completely lost.