Why The Sky Is Blue

It has everything to do with optics.

• When light strikes a smooth flat surface like ice, its visible rays generally pass straight through without their paths being disturbed. This is why glass and ice often appear clear.
• When light st...

Some kinds of light make you more alert and more awake, and others have less of an effect:

• Sunlight is strong in blue, short-wavelength light, although it includes all other colors as well. That’s important in the morning when we need to be alert and awake.
• Your tablet, pho...

We see different parts of the Moon light up at different times of the month. This is because the Moon is at different positions in its orbit around Earth relative to the Sun.

• A full Moon is when the Moon, Earth and Sun are lined up. The sunlight shines on the whole l...