Which among the following is a physical change

Cutting a log of wood into small pieces

A physical change involves a change in the form or appearance of a substance without altering its chemical composition. In this case, cutting a log of wood into smaller pieces is a physical change because:

• No new substances are formed: The wood remains wood; only its size and shape change.
• Reversibility: While physically challenging, theoretically, the pieces can be reassembled into the original log, indicating a reversible change.

In contrast, the other options are chemical changes:

a) Burning of wood: This is a chemical change because it results in the formation of new substances like ash and carbon dioxide.

b) Ripening of fruit: This involves chemical processes that change the fruit's composition, making it sweeter and softer.

c) Cooking of food: Cooking alters the chemical structure of food, creating new substances and flavors.

Understanding the distinction between physical and chemical changes is fundamental in chemistry, as it helps in identifying whether a process can be reversed and whether new substances are formed.