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History’s Creepiest Healthcare Workers

Plague doctors are best remembered for their strange bird-like masks, long coats and wooden canes. They appeared during outbreaks of plague in Europe, especially during the 1600s, when cities hired doctors to treat infected patients and record deaths. The famous beaked mask was not just for show. At the time, many people believed disease spread through “bad air,” so the beak was packed with herbs, spices or flowers to filter out foul smells. It did not actually stop the plague, but it shows how medicine was trying to make sense of disease before germs were understood.

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Why do Glow Worms Glow?

Bioluminescence is the ability of living organisms—like fireflies and deep-sea creatures—to produce light through a chemical reaction using luciferin and the enzyme luciferase. This glowing ability helps them attract mates, lure prey, or hide from predators.

Did you know: Some squid can control their light patterns to communicate in the dark ocean!

* This topic has been previously featured. Spaced repetition improves your learning by helping you retain information for longer.

The Stirling Engine

Is a clever piece of engineering that turns heat into motion. Unlike a petrol or diesel engine, it does not rely on explosions inside the cylinder. Instead, it uses an external heat source, such as solar energy, waste heat or gas, to warm and cool a sealed gas inside the engine.

As the gas heats up, it expands and pushes a piston. As it cools, it contracts, pulling the system back and allowing the cycle to repeat. This simple process can be used to drive a flywheel, generator or mechanical load.

Throwing Heavy Spheres Really Far

Shot put is one of athletics’ purest tests of explosive strength. The aim is simple: launch a heavy metal ball as far as possible from inside a small throwing circle. But behind that short throw is a mix of power, balance, timing and technique.

Athletes use either a glide or rotational technique to build momentum before releasing the shot from the shoulder. The best throws are not just about brute force; they rely on transferring energy from the legs, through the core, and into the arm at exactly the right moment.

Why the Atlantic and Pacific Look Like They Don’t Mix

The Atlantic and Pacific do mix, but not instantly. Where they meet, the water can have different salt levels, temperatures, sediments and currents.

These differences affect the water’s density, which can create a visible line or colour change between the two oceans. Over time, waves, tides and currents gradually blend them together. So, they are not separate like oil and water, they just mix slowly.

Compulsory Voting

Australia is one of the few countries in the world where voting is mandatory. Every citizen aged 18 and over must enrol and vote in federal, state, and local elections — or risk a small fine. Introduced in 1924, the system keeps turnout consistently above 90%, ensuring elections better reflect the will of the people. Similar laws exist in countries like Belgium, Brazil, Singapore, and Argentina, though enforcement varies widely around the world.

* This topic has been previously featured. Spaced repetition improves your learning by helping you retain information for longer.

Ray Dalio - leadership failures and triumphs

Is an American investor, author and founder of Bridgewater Associates, one of the world’s best-known hedge funds. He started the firm in 1975 from his apartment and built it into a major force in global finance.

Dalio is best known for his book Principles, where he explains the lessons he learned from investing, leadership and failure. His writing focuses on decision-making, economic cycles and the idea that people should learn from mistakes rather than hide from them.

Top Gear

Top Gear became more than just a car show because it mixed motoring with entertainment, humour and ridiculous challenges. What started as a straightforward review program evolved into a global hit built around fast cars, road trips, races and over-the-top experiments.

The show’s appeal came from making cars exciting even for people who were not car enthusiasts. Supercar reviews sat alongside budget car challenges, celebrity laps and wild engineering ideas that often went hilariously wrong.

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