💡 Big question

What is everything made up of? Thinkers in ancient India and Greece asked this more than 2,000 years ago — long before any experiment could check the answer.

Long ago, Acharya Kanada in India said that if you keep dividing matter ( dravya ) again and again, you finally reach the smallest particle that cannot be divided — a parmanu . In Greece, Leucippus and Democritus called such indivisible particles atomos (Greek for “indivisible”). At this stage the atom was only an imaginary idea , not something proven by experiment.

Who first proposed that matter is made of indivisible particles?
Roots of Atomic Theory Kanada (India): parmanu Democritus (Greece): atomos Dalton 1808: first scientific theory
  • Acharya Kanada (ancient India) — smallest particle called a parmanu .
  • Democritus & Leucippus (ancient Greece) — called it atomos .
  • These were imaginary ideas , not based on experiments.
What did Dalton propose about atoms?
Dalton's Atomic Theory
All matter is made of tiny indivisible particles called atoms, the building blocks of matter.
  • In 1808 , John Dalton gave the first scientific atomic theory.
  • All matter is made of tiny indivisible particles called atoms .
  • Atoms are the fundamental building blocks that cannot be broken further (as believed then).
✅ Test Yourself
  1. Who called the smallest indivisible particles parmanus ?
    Show Answer Hide Answer
    Acharya Kanada, in the Sanskrit text Vaisesika Sutras .
  2. What does the Greek word atomos mean?
    Show Answer Hide Answer
    Indivisible — it cannot be cut any further.
  3. In which year did John Dalton propose his atomic theory?
    Show Answer Hide Answer
    In 1808. It was the first theory based on scientific experiments.
  4. Was the early idea of the atom based on experiments?
    Show Answer Hide Answer
    No. It began as an imaginary, philosophical idea.
Important Definitions
  • Atomos — indivisible particle (Greek); the Greek idea of the smallest particle of matter.
  • Parmanu — the smallest particle that can no longer be divided, proposed by Acharya Kanada.
  • Dalton's atomic theory — all matter is composed of indivisible particles called atoms, the fundamental building blocks of matter.
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