In Death Valley, California, large rocks have left trails behind them as if they are sailing across the desert of their own volition. For centuries, folks have wondered at the strange phenomenon before scientists tracked the stones and discovered that they are moved by some pretty simple weather patterns—rocks are moved by rare occurrences of rainfall, which turns to ice at night, and melts during the day. A combination of this slick melting ice and a particularly slimy cyanobacteria that live in the soil, surface winds push these stones along the surface, leaving their signature traces.
- What causes stones to sail?
- What weather phenomenon are necessary for this to happen?
- Could we predict when stones are likely to move based on weather?
Rain is the first ingredient for sailing stones
Surface winds then push the stone across the desert, forming trails in their path. It's difficult to model and display surface winds, but this dataset can give you an idea of weather pattern winds.
Ice is formed as the rainwater on the surface freezes, lifting the rocks from the surface of the sand.
- C1: Patterns
- C2: Cause and Effect
Disciplinary Core Ideas
- ESS2.D: Weather & Climate
- PS2.A: Forces and Motion