Which statement best describes how solid objects feel, given the atomic structure described?

• A. They feel solid because of the interaction with our hands; we do not pass through rocks
• B. They feel solid because atoms are densely packed
• C. They feel solid because space is not empty
• D. They feel solid because light cannot penetrate them

Answer: (A)

Feeling solid comes from the electromagnetic repulsion that occurs at the contact surface between your skin and the object. When your skin touches a rock, the electron clouds surrounding the atoms repel each other, creating a strong short-range force that prevents the atoms from passing into one another. That boundary force is what you actually feel as solidity, and it’s why you can’t pass through rocks.

The idea that atoms are densely packed contributes to the overall structure of a solid, but the immediate tactile sensation comes from the surface interaction, not just how tightly packed the atoms are. Statements about space not being empty or about light failing to penetrate don’t explain the touch sensation; they aren’t the mechanism behind why solids feel solid.