How To Use An Analytical Balance

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The purpose of an analytical balance is to calculate mass to an extremely precise and accurate degree. Certain measures are taken in its design to ensure this high level of accuracy. The highest precision analytical balances have weighing pans which are enclosed by transparent doors so that not even an errant draft or speck of dust will alter the balance’s results. An analytical balance works by balancing the load on the platform with an electromagnetic force. The amount of current that is required to exactly balance the load will be proportional to the load on the platform. Because the current is precisely known, the load will be able to be precisely determined.

Some tips to ensure the most accurate results with an analytical balance:

Since natural convection can cause air currents inside the balance, care must also be taken to weigh the object or sample at room temperature.

Be sure to place the balance on a vibration free table or bench.

If you have an older model analytical balance, you will need to calibrate it at regular intervals using a standard mass. This isn’t ...
... necessary with newer balances, which usually are equipped with built in calibration masses.

If you are doing several weightings in a row, be sure to follow the same exact process every time.

Use paper or dishes to measure the mass of powders. For objects, use tongs, gloves, or other fingerprint shields.

If you are weighing hygroscopic materials, be prepared to work quickly. These materials tend to absorb water during the process, which alters results.

Always level and zero the balance. After you have done this, be very careful not to place objects on your table or bench, as this can affect the results. Also, watch your step. A good bump can vary results, too.

Directions for Proper Use of an Analytical Balance

1. First, level your balance. Locate the leveling bubble. It should appear centered at the floor of the weighing chamber. If the bubble is off center, a turn of the balance’s leveling screws (often located at the base and in back of the balance) should fix the problem.

2. Zero your balance. Close the balance’s doors. Depress the zero or control bar buttons (usually located at the front of the balance). When a all zeros appear, the balance has been successfully zeroed.

3. Tare your container, if you are using one. You will always need to use a weighing container if you are weighing liquids, granules, or powders. The process is simple. Place the container on the balance’s pan, close the doors, press the control button or bar, and wait for the zeros. Now the balance knows to automatically subtract the weight of the container from the final results.

4. If you just finished the tare process, remove the container and add your substance. Put the container back on the pan. If not, using tongs or other tool, place the object on the balance pan. Close the doors.

5. The display now shows the mass or weight of your substance or object.