Physicscalendar_todayLast updated: Apr 2026
What is Entropy?
/ˈentrəpi/
A measure of the disorder or randomness in a system. The second law of thermodynamics states that entropy in a closed system always increases — the universe constantly moves towards disorder.
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Everyday Example
A messy room is high entropy; a tidy room is low entropy. Left alone, rooms get messier — it takes energy (your effort) to create order. The universe does the same on a cosmic scale.
publicReal-World Application
“Data centres generate enormous heat because computing requires managing entropy. Every calculation increases the entropy of the universe slightly — it's an unavoidable physical cost of information processing.”
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Did you know?
Rudolf Clausius coined the term entropy in 1865. Ludwig Boltzmann later showed that entropy is fundamentally statistical — a high-entropy state simply has more possible arrangements.
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Key Insight
Entropy explains why time only moves forward. Processes that increase disorder are statistically irreversible — you can't un-break an egg because the odds of all its molecules reassembling are essentially zero.
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