Lesson 10 — Fair Test: Freeze–Thaw Weathering

Earth and space sciences plus inquiry. Students model mechanical weathering by freeze\u2013thaw (frost wedging): they fill a sealed container ('rock') with water, predict what freezing will do, and plan a fair test \u2014 changing the temperature while keeping the container size, water amount and time the same. After freezing, they observe that the expanding ice cracks the container, just as water repeatedly freezing in rock cracks widen it over thousands of years (producing the characteristic straight cracks). Uses the shared Fair Test Investigation Template. Includes a slide deck with an animated freeze\u2013thaw cross-section (water seeping in, freezing, expanding, cracking) and the Freeze\u2013Thaw Investigation worksheet. Safety: seal the container in a bag before freezing.