Use of Balances and Weighing

Section 1: Understanding the Use of Balances

A balance is a precise instrument used to measure mass of substances required for experimental procedures.
Can be analytical (measuring to the nearest 0.0001 g) or top-loading (measuring to the nearest 0.01 g).
Accuracy and precision are key to ensure validity of scientific experiments.
Need to be used on a flat, stable surface, away from drafts and vibrations.

Section 2: Weighing Techniques

Internal Calibration: Some balances self-calibrate, but if not, use known weights to check and adjust the balance.
Always zero the balance before use. This guarantees accuracy.
Use clean, dry weighing containers to hold the substance being weighed.
Always handle the weighing containers with tweezers or wearing gloves to prevent contamination.
Do not overload the balance. It may damage the sensitive mechanism.

Section 3: Weighing Solid Substances

Spatulas or a scoopula are typically used for transferring solid substances to the weighing containers.
Add small amounts gradually. It’s easier to add more than to remove the excess.
Record the mass to an appropriate degree of precision.

Section 4: Weighing Liquid Substances

Section 5: Preventing and Identifying Errors in Weighing

Static electricity, dust, and air currents can affect balance accuracy.
Keep the balance clean and free of debris.
Always close balance doors and wait for the reading to stabilize before recording.
If the reading shows an unexpected change, check for possible errors and resolve them.

Section 6: Safety and Maintenance in the Use of Balances