The 2019-2020 Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition was a year-long drift experiment in the central Arctic with the goal of better understanding how the Arctic system works: how its ocean, sea ice, atmosphere and ecosystem interact with one another throughout an entire year. Sea ice geophysicist Melinda Webster was deployed to the field campaign during one of the most transformative times of the year, from spring to autumn. This period was rich with opportunities to study the seasonal evolution of the sea ice cover as it transitioned from a cold, snow-covered icescape to a fragmented ice pack riddled with melt ponds and drifting rapidly away from the North Pole. This presentation will explain the seasonal evolution of Arctic sea ice processes and properties, how they connect to the big picture of the Arctic system and climate change, and why the combination of field data, satellite measurements, and climate model experiments is one of the most powerful tools in science.