The document discusses tides, including their causes and effects. It notes that tides are caused by the gravitational pull of the moon, sun, and earth. Spring tides occur during moon phases when the sun and moon are aligned, resulting in very high and low tides. Scientist can predict tides using tide gauges. The document also describes an experiment that shows larger, heavier objects standing in for the moon cause higher tides in a bucket of water than smaller, lighter objects, demonstrating larger celestial bodies create greater tidal forces.