Why is it advisable to cool an oven-dried sample before weighing?

Cooling an oven-dried sample before weighing is advisable to ensure accurate measurement. When a sample is heated in an oven, it can retain heat and may still be influenced by the surrounding environment, leading to temperature-induced errors in weight.

Air can create convection currents around the hot sample, and this thermal disturbance can result in an inaccurate reading when the sample is placed on a balance. Weighing the sample at room temperature eliminates this variable, allowing for a more precise and reliable measurement as the sample will not lose mass due to evaporation or gain mass due to atmospheric moisture. Ensuring the sample is at a stable, ambient temperature aligns with standard laboratory practices to achieve consistency in measurements, which is critical for reproducibility and accuracy in materials engineering assessments.