Ask the Expert Question-and-Answer Archive

by Ron Joseph

February, 2005

Density vs. Viscosity

Q. What is the relationship between Density and Viscosity?

A. To the best of my knowledge there is no relationship obvious between density and viscosity. At the extreme, mercury has a VERY high density, 13.6 g/cc at room temeprature, but its viscosity is very low the this metallic liquid can easily be poured. Water, which also pours easity has a density of only 1 g/cc. Honey (syrrup) that we pour over our pancakes has a high viscosity at room temeprature, but when we heat it in a pot of hot water, its viscosity drops so dramatically that we can pour it quite easily. Yet its density remained the same.

I hope this helps.

Best wishes,

Ron Joseph