Science
How Do Rainbows Form?
Rainbows form when raindrops bend and reflect sunlight. See why the Sun must be behind you, where the 42-degree angle comes from and what causes a double bow.
Science
Clear answers to how the physical world works, from light and heat to atoms, energy and numbers, with every fact traced to its source.
Science
Why Is the Sky Blue?
The sky is blue because air molecules scatter short-wavelength blue sunlight more than red. The same effect, Rayleigh scattering, turns sunsets red.
Science
Why Does Ice Float on Water?
Ice floats because freezing locks water molecules into an open hydrogen-bonded lattice, making ice about 9 percent less dense than the liquid water below.