John Dalton was born in 1766 into a poor weaver’s family in England. He began his career as a teacher at the age of twelve and, seven years later, became a school principal. In 1793, he moved to Manchester to teach mathematics, physics, and chemistry at a college, where he spent most of his life teaching and conducting research. In 1808, he presented his atomic theory, which marked a turning point in the study of matter.
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NCERT CLASS IX Science