GREAT EXPERIMENTS
Cavendish's Torsion Balance: How a Hermit Weighed the Earth in His Garden Shed
In 1798, Henry Cavendish measured the gravitational attraction between two lab-sized lead balls and used it to derive the mass of the planet. The experiment was so sensitive that his own body heat was the loudest source of noise.
What this story trains
How do you measure something that has no external reference frame? Cavendish's answer: solve for the missing constant in Newton's equation, then derive the rest from observations you already had.
Logical ReasoningWorking Memory
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The full version is a Daily Nutrition session: progressive text reveal that pauses at sentence boundaries for embedded multiple-choice questions tied to the reasoning. You cannot skip ahead; the next paragraph unlocks when you engage with the current one.