Introduction:
Burning of wood and cutting it into small pieces are two different types of changes as they involve distinct processes and result in different outcomes. These changes can be explained based on the concepts of physical and chemical changes.

Physical Changes:
A physical change refers to a change in the physical properties of a substance without altering its chemical composition. When wood is cut into small pieces, it undergoes a physical change. This is because cutting wood into smaller pieces does not involve any chemical reactions. The chemical composition of wood remains the same, and only the size and shape of the wood change.

Chemical Changes:
A chemical change, on the other hand, involves a change in the chemical composition of a substance resulting in the formation of new substances with different properties. When wood is burned, it undergoes a chemical change known as combustion. During combustion, the wood reacts with oxygen in the air to produce heat, light, and various gases such as carbon dioxide and water vapor. The chemical bonds in the wood are broken, and new substances are formed.

Key differences between burning and cutting wood:
1. Process: Cutting wood involves a physical process of dividing the wood into smaller pieces using tools such as saws or axes. Burning wood, on the other hand, involves a chemical process of combustion.

2. Chemical composition: Cutting wood does not alter the chemical composition of the wood. The same elements and compounds are present in the cut pieces as in the original wood. In contrast, burning wood results in the chemical decomposition of wood, leading to the formation of new substances.

3. Energy transformation: Cutting wood does not produce any significant energy transformation. It is a mechanical process that requires energy input. Burning wood, however, releases a large amount of energy in the form of heat and light as a result of the chemical reactions occurring during combustion.

4. Reversibility: Cutting wood is a reversible process. The cut pieces can be reassembled or used for various purposes without any chemical changes. Burning wood, on the other hand, is an irreversible process. Once the wood is burned, it cannot be restored to its original form.

Conclusion:
In summary, the burning of wood and cutting it into small pieces are considered as two different types of changes. Cutting wood is a physical change that alters the size and shape of the wood without changing its chemical composition. Burning wood, on the other hand, is a chemical change involving the decomposition of wood and the formation of new substances. Understanding these differences helps us comprehend the various processes and outcomes associated with these changes.