Desert Winds

This week we had a special treat - Maria Waller (a geology professor at Wellesley and former 1-2 parent) did a demonstration of how winds can shape deserts. Using a hairdryer to supply the wind, she showed how in rocky deserts smaller grains of sand  and particles are blown away leaving a rocky "desert pavement" behind. In sandy deserts, blowing winds create hills of sands called dunes. Over time, these dunes are pushed by the same winds, moving slowly across the desert.

Students had two learning experiences connected to this presentation. In the first, small groups were given two rocks to examine: one which had been weathered by wind and another which had been worn by water. The goal was to determine which stone had been exposed to which type of erosion. Our conclusions were that the smoother of the stones had been evenly worked over by flowing water like that of a stream or river. The other stone had been shaped by winds over time showing the same spiny ridge we observed on the tops of the sand dunes.

In our other exploration, pairs of students were given a cup of wet sand, a cup of dry sand, and a pair of straws. Our students provided the "wind" on the sand and observed its effects on both types of sand.