Why don't oil and water mix?
Salt dissolves in water; oil does not. But why? You can think of that glass of water as a big, bumpin' dance party where the water molecules are always switching dance partners -- and they'd much rather dance with a salt ion. John Pollard explains how two chemistry principles, energetics and entropy, rule the dance floor.
Where did Earth’s water come from?
Water covers over 70% of the Earth, cycling from the oceans and rivers to the clouds and back again. It even makes up about 60% of our bodies. But in the rest of the solar system, liquid water is almost impossible to find. So how did our planet end up with so much of this substance? And where did it come from? Zachary Metz outlines the ancient origins of water on Earth
Why does ice float in water?
"Water is a special substance for several reasons, and you may have noticed an important one right in your cold drink: ice. Solid ice floats in liquid water, which isn't true for most substances. But why? George Zaidan and Charles Morton explain the science behind how how hydrogen bonds keep the ice in your glass (and the polar ice caps) afloat." View the complete lesson at TED-Ed.