Make NGSS come alive with this 4th grade science story about motion, speed, and the energy behind one unforgettable crash. Aligned to 4-PS3-1, The Boulder That Flattened a Town is a narrative science lesson based on a real event in the Italian Alps — when a massive boulder broke free from a cliff, gained speed, and plowed through everything in its path. This Story: The Boulder That Flattened a Town Standard: 4-PS3-1 Students explore how energy is related to the motion of an object — and how s