Question

Why does a glass containing an iced beverage feel cold?

Molecules in the glass are moving faster
than molecules in the skin.

Molecules in the skin are moving faster
than molecules in the glass.

Answer 1

The second statement is correct: molecules in the skin are moving faster than molecules in the glass.

Why: temperature measures the average kinetic energy of molecules. A cold glass (cooled by the iced drink) has lower average molecular motion than your skin, so heat flows from your warmer skin into the colder glass by conduction. That loss of heat from your skin activates cold receptors and makes the glass feel cold. (How cold it feels also depends on the rate of heat flow — materials with higher thermal conductivity draw heat away faster and feel colder.)