Joseph Proust discovered in the 18th century that the masses of elements in a chemical compound are in a definite ratio. For example, in copper carbonate the mass of copper is always 5.3 times the mass of carbon and the mass of oxygen is always 4 times the mass of carbon. John Dalton later expanded on this with his atomic theory in the 19th century, proposing that compounds are formed by the combination of atoms in specific definite ratios. Isaac Newton also discovered that the force of gravitational attraction between objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

2. RATIO AND PROPORTION
APPLICATION

3. RATIO IN CHEMISTRY
In chemistry things are classified as elements and
compounds. In the eighteenth century Joseph Proust found
out that the masses of the elements in a compound are in a
definite ratio.

4. For example, he found through experiments that in any
quantity of copper carbonate, the masses of copper is 5.3
times and the mass of oxygen is 4 time that of carbon.

5. The idea of atom may have been motivated by the
thought that if we consider very small particles of
elements , such comparisons for compounds can be
done using natural numbers. This idea was first
presented by John Dalton in the 19th century.

6. According to Dalton’s theory , compounds are formed by
the combination of very small particles of elements
called atoms; and in any particular compound , the
number of atoms of the various elements are in a
definite ratio.

7. Universal proportion
A basic principle of Physics is that all objects in the
Universe attract one another. This principle says that
this force of attraction is directly proportional to the
product of the masses and inversely proportional to
the square of the distance.

8. This was formulated by she famous English scientist ISSAC
NEWTON in the seventeenth century.