Final answer:
If supercooling occurs during an experiment to record the freezing temperature, initiate freezing by introducing an ice crystal or shaking the container, then record the temperature at which ice formation begins. Supercooling allows water to remain liquid below 0°C, but the actual freezing point must be measured after inducing crystal formation to ensure accurate results.
Step-by-step explanation:
When recording the temperature at which freezing occurs, and supercooling is observed, it's important to note that supercooling is a condition where water remains liquid below its normal freezing point. In experiments, if supercooling occurs, it is critical to ensure that freezing is initiated to accurately determine the actual freezing point of the water. This can often be done by introducing a small ice crystal or by shaking or tapping the container to induce ice nucleation. Once freezing commences, you then record the temperature. This is usually around 0°C for pure water but can vary for solutions containing antifreeze solutes.
Supercooled water can exist significantly below 0°C without freezing due to the lack of nucleation sites or the presence of antifreeze proteins that inhibit crystal formation. Such phenomena occur not just in laboratory settings but also in nature; various organisms produce these proteins to survive in cold environments. Yet, for experimental purposes, especially when trying to determine the freezing temperature of a solution, it is essential to eliminate the effect of supercooling to get a precise measurement.
During an experiment, if you notice that the temperature of the water in your test tube drops below 0°C without forming ice, take steps to trigger the freezing process. Only after this can you accurately record the freezing temperature which should be 0°C for pure water under standard atmospheric pressure.