Discussion Questions: Life's Little Essential: Liquid Water

What is the argument in favor of the idea that liquid water is essential to life? What other substances have been proposed?
Do you think life could have gotten started without water?
Why is it important that solid water (ice) floats rather than sinks?
How is it possible for all three states of water to coexist on Earth at the same time?
Why do planetary scientists search for evidence of liquid water on other planets?