Walking on a Frozen Sea •the ocean can freeze up to 1–3 meters thick in Antarctica thick enough to carry people and even heavy vehicles. •Sea ice isn’t just frozen water—it’s seawater mixed with salt crystals, so it looks rougher and more matte than lake ice. •When the ocean freezes, it literally expands, creating cracks and pressure ridges that look like broken glass on a giant scale. •Walking on sea ice means you’re standing on top of the ocean, not landthere’s liquid water right beneath your