#light
Questions about “light”.
15 articles
How do fireworks get their colors?
Great bursts of red, green and blue across the night sky. Those vivid colors are not painted on. And the fireworks people watched in old Edo looked completely different.
Why do we see lightning before we hear thunder?
A flash, then a pause, then the rumble. Lightning and thunder are born in the same instant, so why do they reach us at different times? That gap has also served science remarkably well.
What happens if you light a candle in space?
A candle flame always points upward. So what shape would it take in space, where there is no up or down? Astronauts have actually tried it.
Why do soap bubbles shimmer with rainbow colors?
Soapy water itself is almost perfectly clear. Yet the moment you blow a bubble, swirling patterns of color start dancing across its surface.
Do mirrors really reverse left and right?
Raise your right hand in front of a mirror, and the person in the glass seems to raise their left. So why doesn’t a mirror flip you upside down?
Why is the night sky dark?
When the Sun goes down, it gets dark. That obvious fact turns out to be a puzzle that troubled astronomers for centuries.
Why is the sea blue?
The sea is blue because it reflects the sky—or so we’re often told. But when one scientist put that to the test aboard a ship, it turned out to be only part of the story.
Why is milk white?
Milk poured into a glass is a dazzling white. Yet search the milk from top to bottom, and you won’t find a single “white pigment” responsible for it.
Why are plants green?
Fresh spring leaves, deep summer forests: why are plants so uniformly green? Behind that question lies a surprisingly deep puzzle: why aren’t they black?
Why do chameleons change color?
Chameleons are famous for shifting color to melt into their surroundings. But when researchers took a closer look, the story turned out to be rather different.
What is the nearest star to the Sun?
Of all the countless stars in the night sky, which one is our closest neighbor? Surprisingly, it is a star you cannot see with the naked eye.
Why do we sneeze?
Once your nose starts to tickle, there’s no stopping it. Bright light can set it off, and some claim sneezes are as fast as a bullet train. How much of that is true?
What was the first photograph?
We snap dozens of photos a day on our phones. But taking the very first one in the world called for extraordinary patience.
When were eyeglasses invented?
We wear them every day as if they were part of our face. Thanks to one friar’s sermon, we know surprisingly well when this little device was born.
Are sunsets on Mars blue?
Mars is known as the Red Planet. When a rover photographed the Sun setting in its sky in color, the scene it captured looked nothing like a sunset on Earth.