Question

why do we feel cold when we touch a piece of ice

Answer 1

Hi
We feel cold when we touch an object or matter like ice at a lower temperature than our body temperature. This is because the heat from our body being higher in amount moves to the ice through our skin(by thermal conduction) in order to attain thermal equilibrium between the iceand the body.
hope you understand

Answer 2

we feel cold when we touch a piece of ice because ice have low temperature than our body