What factor explains why the bulk density shipping weight differs from laboratory density?

What factor explains why the bulk density shipping weight differs from laboratory density?

• A. impurities in the shipping material
• B. air mixed in with the shipping material
• C. scales for shipping materials are less accurate
• D. bulk weight uses trade weigh, which is 5% more

Answer: (B)

The key idea is that bulk density includes the air spaces between particles. When a material is shipped loose, air is trapped among the grains, so the bulk volume contains voids and the mass per that volume is lower. Laboratory density, on the other hand, reflects the solid material itself with little to no air, so it yields a higher density. That difference in how much air is present in the packed material explains why the bulk density shipping weight differs from the laboratory density. Impurities, measurement instrument accuracy, or a supposed 5% trade weight don’t account for the physical difference between bulk packing and the solid material density.

The key idea is that bulk density includes the air spaces between particles. When a material is shipped loose, air is trapped among the grains, so the bulk volume contains voids and the mass per that volume is lower. Laboratory density, on the other hand, reflects the solid material itself with little to no air, so it yields a higher density. That difference in how much air is present in the packed material explains why the bulk density shipping weight differs from the laboratory density. Impurities, measurement instrument accuracy, or a supposed 5% trade weight don’t account for the physical difference between bulk packing and the solid material density.