why one should not weigh a hot object on an analytical balance?

One should not weigh a hot object on an analytical balance because the heat causes convection currents (air movement) around the object and balance pan, which disturbs the measurement and makes the mass readout unstable and inaccurate. Additionally, hot air has a lower density than ambient air, causing buoyancy effects that alter the apparent weight of the object. This results in an erroneous, usually lower, reading. Also, the heat can affect the balance's sensitive components and potentially damage the instrument. Therefore, it is important to wait for the object to cool to room temperature before weighing on an analytical balance to ensure accurate and stable results.