The consolidation of snow

January 06, 2016


I was always on the losing side of a snowball fight, until I joined Jenike & Johanson. Snowballs lofted at me by my enemies would invariably leave a mark, whereas snowballs that I tossed would disintegrate as they sailed towards my target. I needed to better understand the requirements for crafting stronger snowballs.

Because snow is essentially a bulk solid, I knew that by measuring its cohesive strength, I would be able to determine the pressure necessary to produce a snowball with better integrity. Our laboratory is equipped with both direct and annular ring shear testers that measure strength. Finding time in the lab was a challenge, as our testers are constantly in use. We endlessly apply their results to design hoppers, bins, silos, processing vessels, and transfer chutes and solve bulk solids handling problems for clients all over the world, using methods and analyses developed by Andrew Jenike. Fortunately, I was able to break into the lab schedule. By measuring the cohesive strength of snow over a range of consolidation pressures and measuring the gain in strength when remaining consolidated over a period of time, I used the data to improve my snowball manufacturing process.

My test results were insightful. I realized that that the pressure that I applied when packing the snow was too low to produce a strong snowball, which was why my mortars were so ineffectual. I hypothesized that I should be able to increase the strength of my snowballs dramatically by keeping them compacted in my hands for a short period of time.



During the next snowball fight, I was able to validate my thesis. Increasing consolidation time indeed was more effective than increasing consolidation pressure. Unfortunately, my wisdom had little effect on my ability to aim. My neighbor sent me a bill for $200 for the repair of his window.

Jenike & Johanson can’t help you with your aim, but if you need help with testing materials don’t hesitate to get in touch with us!

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