GRANATARIA BALANCE: CHARACTERISTICS, PARTS AND HOW TO USE IT - CHEMISTRY - 2025

The granatary balance is a laboratory instrument to be able to measure the masses of certain objects and chemical substances. Its precision is high (0.001g), and its capacity range ranges from 200g to even 25Kg. Therefore, there are different varieties of these scales depending on the type of measurement required.

It is one of the most widely used mechanical balances, as it has certain advantages over the analytical balance. For example, it is cheaper and more durable, takes up less space and takes less time to care for as it is more rudimentary (although it should always be kept clean). It also allows to determine the mass of light and heavy objects on the same plate.

Granataria balance. Source: Penpitcha Pimonekaksorn

This instrument is also known as a weighing scale. To use it, it is essential to calibrate it where it is located with specific masses. If it moves out of place, for whatever reason, it should be recalibrated before making mass determinations.

Characteristics of the granataria scale

The granataria scale generally has the following characteristics:

- It has three beams where the weights or trestles rest that serve to compare and determine the mass of the object. In fact, in English this balance is known as triple beam balance (triple arm balance), exactly for this characteristic.

- Its precision can be from 0.1 to 0.001g. This increases if the scale has an extra arm or beam that is smaller and thinner compared to the others.

- It can be heavy, depending on your capacity.

- Its use is unlimited as long as it is calibrated and does not suffer irreparable physical damage.

Parts

Plate

From the image above it can be seen that this balance has a plate or saucer, and on it the sample whose mass is to be determined will be placed. This must be kept as clean as possible, since some granatary balances are very sensitive to dirt and the wrong masses can be obtained as a result.

Point of support and support

At its bottom, there is a fulcrum. Its function is to prevent the plate from tilting due to the weight of the object that is placed on it.

Likewise, the whole scale has a support; that for the balance of the image, it is white. This stand simply takes care of fully supporting the instrument.

Leveling screw

At the same point of support you can see a silver thread, which is the leveling screw. With this screw, the balance is calibrated before taking measurements.

Faithful and pointer

The stick and pointer, also called the fixed and moving marks, respectively, are at the opposite end of the balance plate. In the image below you can see that the pointer, as its name indicates, points towards the faithful, which is where the number 0 is marked.

Taring the balance. Source: GOKLuLe 盧 樂

When the stick and pointer line up or coincide, the balance is tared; that is, you can begin to determine the mass of the object. Again, the mass will not have a reliable value if at the end the pointer does not point to 0, ending the weighing.

Scale arms

In the scale arms are the measurements, as if they were rules, to know the mass of the object. In these arms or beams are the small weights or trestles, which move to the right until the pointer is adjusted towards 0.

What is it for?

As is already known, it serves to determine the mass of certain objects; but in a laboratory, their nature varies a lot. For example, it can be useful in determining the mass of a precipitate formed in a previously weighed container.

It can also be used to calculate the yields of a reaction where a considerable amount of product was formed. Thus, in a clean container whose mass is tare aligning the faithful and pointer, the product is weighed and then the performance calculations are carried out.

How to use it?

From the other sections the question arises: how is the balance used? The empty container is first placed on the plate, and the weights are moved to the left side. If when doing this the pointer does not coincide with the faithful or the 0 mark, adjust the screw under the plate to complete the taring.

Then, the object or product whose mass is to be determined is placed inside the container. When you do, the pointer will stop pointing at 0, and you have to align them again. To achieve this, the weights must be moved to the right, starting with the largest and heaviest.

This weight stops moving when the scale stops rocking so much; It is at that moment that the second, smaller weight begins to move. The procedure is repeated with the other weight until the pointer indicates 0.

It is then when we can obtain the mass, and for this we simply have to add the values ​​indicated by the weights in their respective scales. The sum of these values ​​will be the mass of the object or product.

Examples of mass readings

Mass measurement with a granatary scale. Source: Penpitcha Pimonekaksorn

What is the mass of the object according to the scale in the image above? The large weight indicates that the mass is between 200 and 300g. The one on the back, for the 0-100g scale, indicates 80g. And looking now at the smallest weight, for the 0-10g scale, it points to about 1.2. Therefore, the mass read for the object is 281.2g (200 + 80 + 1.2).

Another example of measurement. Source: GOKLuLe 盧 樂

And to finish we have this other example. Note that here this time there are four arms or beams.

The largest weight is below 100g, so the mass of the object is between 0-100g (second scale from back to front). The second weight contains the number 40, so the mass is 40g. Then, on the third scale (0-10g) it is seen that the weight is very close to 8.

How do you know in that case if it is 7 or 8g? To find out, just look at the fourth scale (0-1g). In it, the weight indicates 0.61. Therefore, it cannot be 8.61 if we add both readings, but 7.61. Then adding all the masses we will have: 40 + 7 + 0.61 = 47.61g.

However, there is a detail: the pointer is not aligned with the faithful (right of the image). This means that the weights still need to be adjusted and the 47.61g mass is not really correct.

History of the granataria balance

The granataria scale is dated between the 15th and 17th centuries. The data are very inconclusive, since at that time there were constant innovations in this type of artifact. For example, Leonardo Da Vinci (1452-1519) developed a graduation for scales that applies this artifact.

After Da Vinci, Gilles Roberval (1602-1675) developed a system of parallels to maintain the balance of the plate on the scale, significantly improving the calibration.

Thus, it was during that time that the granataria scale as we know it would be developed, with the subsequent electronic systems that were added from the 20th century.

Roberval's balance. P.poschadel / CC BY-SA 2.0 FR (https://creativecommons.org/licenses/by-sa/2.0/fr/deed.en)

References

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2. Laboratory instruments. (sf). Granataria balance. Recovered from: instrumentdelaboratorio.info
3. Wikipedia. (2019). Triple beam balance. Recovered from: en.wikipedia.org
4. Triple beam balance: Instructions to use. Recovered from: physics.smu.edu
5. Illinois Institute of Technology. (sf). Using a balance. Science Fair Extravaganza. Recovered from: sciencefair.math.iit.edu
6. Azucena F. (2014). Granataria Balance. Recovered from: azucenapopocaflores.blogspot.com