Intellect PlusPhysics
1,748 cards. Each one is a 40-second story with a five-minute read behind it. Page 30 of 30.
Becquerel's wrapped photographic plate revealed atoms that change into other elementsIn 1896 Henri Becquerel wrapped a photographic plate in black paper, set uranium salts on top, and found it fogged anyway. Something invisible was streaming out of the atoms thems…
Every screen you own fakes millions of colours with three tiny lightsLook closely at any television or phone and each pixel is really three separate specks of red, green and blue light. From normal viewing distance your eye blends them into one sol…
The same law keeps bicycles upright and makes neutron stars spin furiouslySpin something and it resists changes to that spin. That is angular momentum, and in an isolated system its total never changes. The rule explains why a moving bicycle stays uprig…
A jittering speck under a microscope finally proved atoms are real.In 1827 the botanist Robert Brown saw tiny particles from pollen dancing restlessly in water, and nobody could explain why. In 1905 Einstein did: they are being jostled by invisib…
Old church windows are not thicker at the bottom because glass flows.It is a favourite classroom fact: glass is really a slow liquid, and medieval windows have sagged over the centuries. It is not true. Glass is a solid, and calculations suggest me…
Water lasts longer on a very hot pan than on a warm one.Flick water onto a pan just above boiling and it hisses away at once. Make the pan much hotter, around 193°C, and the drops bead up and skate about for far longer. They are hoveri…
A tiny imaginary doorkeeper nearly broke the laws of physics.In 1867 James Clerk Maxwell imagined a being that sorts fast molecules from slow ones through a tiny door, making one side of a box hot and the other cold without doing any work. …
A glass teardrop that shrugs off a hammer but explodes if you snip its tail.Drip molten glass into cold water and you get a tadpole-shaped bead. Hit its round head with a hammer and it survives. Nick its thin tail and the whole thing bursts into powder in…