The temperature drops, water cools, and suddenly, there is a crest of ice on the surface, slowly growing and deepening. Soon it will be so hard that we can touch it without destroying it, and even walk on it. Anyone who has been skating on a lake will know that there is ice and there is ice. Sometimes clear, sometimes so filled with air bubbles as to be almost completely opaque.
The Swedish water investigator Gisela Ahlberg decided to explore this, and devised a method, together with her colleague Christina Weldero, to study natural waters by ice images. Continue reading When water freezes