Final answer:
Chopping wood, bending metal, and cutting a cake are all physical changes because they alter the form of the material without changing its chemical composition. However, frying an egg is a chemical change due to the denaturation of proteins resulting in new substances being formed.
Step-by-step explanation:
The question asks to identify which of the options represent a physical change. A physical change is characterized by a change in the form or state of matter, but the substance itself doesn't become a different substance. A physical change is often reversible.
- A) Chopping wood: This is a physical change because the wood is being cut into smaller pieces, but it's still wood.
- B) Bending metal: Bending metal alters its shape, not its chemical identity, thus it is a physical change.
- C) Cutting a cake: Similar to chopping wood, cutting a cake changes its shape but not its chemical composition, making it a physical change.
- D) Frying an egg: This is a chemical change because the proteins in the egg are being denatured by the heat, causing a permanent change in the chemical nature of the egg.
Therefore, chopping wood (A), bending metal (B), and cutting a cake (C) are examples of physical changes. Frying an egg (D), however, is not a physical change because it results in new substances being formed, hence it's a chemical change.