Remarkably contrasting behavior is displayed by these two frozen, dense sand packs (ice + sand, no open porosity) deformed at identical conditions of pressure, temperature, and differential stress. One sample (red curve) was much weaker, deforming at a far higher rate than the other (blue curve) at a fixed differential stress of 30 MPa. The interesting thing is that the weaker sample had a higher ratio of sand to ice (70.5% sand:29.5% ice by volume) than did the stronger sample (68%:32%). The difference relates to grain-size distribution. The stronger sample had sand particles of approximately equal grain diameter; the softer sample was a mix of sand grain sizes. The results give us a clue about the water content of Martian soil [Durham et al., 2009, GRL].