Correct Answer:
B. Water is denser than ice
The foundational concept here is density. Ice floats on water because water is one of the few substances that becomes less dense in its solid form than in its liquid form. When water freezes, its molecules arrange into a crystalline structure that takes up more space, making ice less dense than liquid water. An object floats if it is less dense than the fluid it is in.
- A: Ice is denser than water is incorrect because ice is actually less dense than water, which is why it floats.
- C: It is more viscous than water is incorrect; viscosity, or resistance to flow, does not explain why ice floats.
- D: Ice has more surface tension than water is incorrect; surface tension is a property of the liquid's surface and does not account for the bulk phenomenon of floating due to density differences.