Physics
Matter, energy, light, and motion.
Physics
Why is the sky blue?
Air molecules scatter short-wavelength light far more strongly than long-wavelength light, so blue arrives at your eye from every direction of the sky while red passes straight through.
5 min read
Physics
Why can't anything travel faster than light?
The limit is not about light — it is the maximum speed at which any cause can reach any effect, and light simply happens to travel at it.
7 min readadvanced
Physics
Why don't birds get electrocuted on power lines?
Electricity only flows when there is a voltage difference across something, and a bird touching one wire has both feet at the same voltage, so there is nothing to push current through it.
5 min read
Physics
Why do mirrors flip left and right but not up and down?
They do not flip left and right at all — they flip front and back, and you are the one who mentally rotates yourself to face your reflection.
5 min read