ساينس الصف الرابع الإبتدئي – الفصل الدراسي الاول In This part we will study : 2. Chemical change Chemical change It is a change in the shape and the structure of matter producing a new substance with different properties. Examples of chemical change: 1. Burning of wood, burning of sugar, burning of paper and any burning process (combustion) is considered a chemical change. 2. Adding yeast to dough as in bread. 3. Iron rust. 4. Rottenness (Fermentation) of fruits. 5. Production of yogurt. Give reason: Adding sodium bicarbonate to vinegar is a chemical change. Because change in shape and structure and producing a new substance. بالتوفيق مستر احمد الباشا