Da Vinci’s fractal trees
Leonardo da Vinci observed that tree branches together are always as thick as the trunk beneath them. This is true, and there are some good ideas why.
Category: Physics & chemistry
Science wars: Non-periodic crystals
Up until 1982, all crystals were believed to be, by definition, periodic. But then an Israeli materials scientist discovered something strange…
Rolling uphill
The mechanical paradox is a device that seemingly defies the law of gravity: a pair of cones that roll uphill.
Sky compass
Bees use sunlight polarisation patterns to navigate. We can train ourselves to detect light polarisation too.
Natural units (Part 2)
Whereas most units of measurement are arbitrary and human, Planck units are based only on four fundamental physical constants. [2 of 2]
Natural units (Part 1)
Most units of measurement are based on specific physical qualities or tangible reference objects. But they don’t have to be. [1 of 2]
The shadow of the volcano
What do the bicycle, Marmite, Mormonism, and Frankenstein have in common? A volcano in Indonesia.
Glowing snails
Just one species of land snail and a few species of freshwater snail glow in the dark.
Fire Diamond 4-4-4
The Fire Diamond categorises hazardous substances according to flammability, instability, and danger to human health. One material ranks the maximum on all three scales.
Underwater ball sports
If you’re playing underwater rugby or football, how do you keep the ball from floating or sinking?
Doomsday device
In 1950 Leo Szilard warned the world that a single device capable of annihilating all life on Earth was theoretically possible.
Longest half-life
Bismuth-209 is radioactive, decaying like any other unstable atom over time and emitting radiation as it goes. But its rate of alpha decay is slower than any other.
The Phenol conspiracy
In World War I, phenol was a key ingredient in aspirin, explosives, and phonograph records. German agents secretly redirected Thomas Edison’s excess phenol supply to prevent it being used for British bombs.
Light of the rocks
Radiocarbon dating only works on organic material, so how do you accurately measure the last time rocks and sediment saw sunlight? Luminescence dating.
Falling bullets
In many parts of the world it is traditional to celebrate by firing guns in the air. But what happens to the bullets?
Natural nuclear power
Enrico Fermi switched on the first human-made nuclear reactor in 1942, but the first natural nuclear reactor on Earth occurred 1.7 billion years earlier.