We are exploring a “magic sandbag” concept - a sandbag that weighs just a fraction of a pound when dry, making it easy to transport in bulk, but swells to around 20 pounds when wet. The idea is to enable archaeologists to bring hundreds of these bags to a dig site with minimal effort, then activate them on-site with water to create instant, heavy barriers to protect excavation areas from rain and erosion. This round of testing focused on experimenting with sodium polyacrylate (a super-absorbent polymer) and hamster bedding as fillers to evaluate weight, volume, and handling characteristics.

Step 1: Measuring the Sodium Polyacrylate

We began by weighing out 7 grams of sodium polyacrylate crystals. This small amount was enough to run our first hydration test.

Step 2: Hydrating the Polymer

After adding water, the polymer swelled into a bright blue gel with a total weight of 1.67 kg - an impressive demonstration of how much water the polymer can absorb compared to its starting weight.

Step 3: Group Observation and Brainstorming

Our team gathered to feel the hydrated gel and discuss its potential as a sandbag filler. The consensus was that it felt “beefy,” flexible, and could work well for absorbing impact, though we noted that leakage control would be important for field use.

Step 4: Measuring and Filling Sandbags

We measured the empty sandbag length, then filled it with the hydrated polymer outdoors to simulate how this process might work on-site for archaeologists.

More time for hands-on work!