To accurately determine the melting point of ice, the correct procedure is:
A. Mix ice with water and immediately measure the temperature.
This method allows you to create an equilibrium between ice and liquid water. When ice is mixed with water, the temperature will stabilize at the melting point of ice (0°C at standard atmospheric pressure) as long as ice is present. Option B would not reliably indicate the melting point because it involves changing the state of water into ice; option C is incorrect because it suggests raising the temperature beyond the melting point; and option D involves measuring the temperature at the point of ice addition, which may not reflect the melting point accurately.