What is bulk density?

Bulk density is defined as the density of a specific amount of a particular matter like powder or soil. In other words, it is the weight of a specific material in a given volume. For example, we can measure the weight of the soil in a specific volume. It is also called apparent density or volumetric density. 

Bulk density can be defined as the weight of fibre per unit volume. This is usually given in gmL – 1 and is a great indicator of structural changes. It is expressed as grams per millilitre which are denoted by g/mL but the international bulk density unit is kilogram per cubic meter (1g/mL=1000 kg/m³). This can also be measured in grams per cubic meter and is denoted as g/m³. 

In this article, we are going to learn more about this topic and how questions of this concept can be solved. Before that, we need to know the bulk density formula and much more about this topic so that we can easily solve any question that comes across. Apart from the formula, we will also learn quite a bit about various things like the importance of bulk density. We have already learned the definition and will learn a couple of other concepts which are vital to understanding. 

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How to calculate bulk density?

So, the question here is how to calculate it. 

The formula to calculate bulk density which is g/m³ is calculated by using the values of the weight of the dry soil and the volume of the soil. 

Therefore, the calculation would be: dry soil weight (g) / bulk volume of the soil (cm³)

This is the formula for how to calculate bulk density. 

To calculate the soil volume, there is a specific procedure. 

The soil volume is the same as the volume of the ring that is used in the experiment. To calculate this volume, follow the instructions below:

1. Measure the height of the ring. Do this with a ruler in centimetres to the nearest millimetre. 

2. After that, measure the diameter of the ring and divide it by 2 to get the radius. 

3. The volume of a ring is = π*r²*height of the ring.

4. For example, if the diameter is 7cm and the height is 10cm, the volume would be *3.5²*10 = 384.65 cm³. This is how you calculate volume before you calculate bulk volume.  

We usually have to calculate dry soil yourself so here is how to do it: 

1. Measure an oven proof container in grams. This would be W1

2. Then remove all the soil and put it into the container. Put that container in the microwave for 10 minutes or you can put it in an oven at 105°C for 2 hours. 

3. Once this soil Is dry, weigh it on the scale. This would be W2. 

4. The dry soil would be calculated as W2 – W1. This calculation would give the value of dry soil in grams. 

Then using this you can calculate the bulk density formula. Don’t forget to add the bulk density unit or else you will lose marks!

Fun Fact - What is the importance of bulk density?

This concept is widely used and holds great importance for economic and functional reasons. High bulk density is more desirable as it helps in reducing costs of packaging and shipping whereas the low bulk density influences powder properties such as instant characteristic or flowability. 

Another importance of bulk density is that it helps to measure how tightly packed the soil particles are. The higher the value for soil, the less favourable it is for the growth of plants as it means it doesn’t have big pores for drainage or aeration. This bulk density measurement can help to measure and come to conclusions about many things. It also helps in decision-making. 

Conclusion

Now that we know the bulk density definition, and a lot more about this topic, it would be quite helpful for us to solve various questions that come in our examination. It is a very important topic and can be quite useful for those in the agriculture department as they can calculate the value for soil the bulk density definition is quite easy to understand and using this you can also help your friends and peers that have a hard time to understand this.