Join Exploratorium Senior Scientist Paul Doherty as he shows us a demo related to Antarctic ice! Paul demonstrates how using Antarctic ice can help tell us what the temperatures of the earth's oceans were, thousands of years ago. In a mixture of water with heavy and light isotopes of oxygen, the light isotope evaporates more quickly at higher temperatures, the light isotope oxygen 16 enriched water vapor falls as snow in Antarctica and records the temperature of the ocean as a function of time.