Have you ever thought about how amazing water is?
Ice is a solid but it floats on its own liquid form, what we know as water. Can you imagine what life would be like if it didn’t? Water would freeze and sink. Ponds would be literally frozen solid. What would happen to fish and other aquatic life forms? What would that mean for us? Our planet?
Luckily, ice does float. As ice forms, it expands making ice is less dense than liquid water. The weird thing about water is that it is most dense at about 39°F (4°C). What does this do to our lakes and ponds as winter sets in?
Right now, chilly air is cooling the water’s surface. The colder water on the surface sinks, bringing warmer water up from below. This effectively mixes the water so that eventually the temperature is uniform throughout. We call this phenomenon “turning over”. It happens in autumn as the ice sets in and then again in spring as the ponds ice out. It mixes up nutrients and distributes oxygen. An odd quirk of water molecules is enormously beneficial to life on earth.
