The Milky Way is the huge group of billions of stars, planets, gas, and dust in which our solar system exists. It has a spiral shape and rotates slowly in space.

Only about 2.5% of all the water on Earth is fresh water. The rest is salt water found in oceans and seas.

Hertz is represented as Hz.
Meter is unit of Length.
Second is unit of Time.

James Watt as a Scottish Engineer.
He invented Steam Engine in 1765.
Steam Engine is not invention of a single person.
First, Thomas Savery in 1698 worked on the steam engine, then Thomas Newcomen in 1712 improved it, and by studying both their ideas, James Watt made the modern engine in 1765.

Aluminum forms almost 8.3% of Earth’s mass.
It is mostly found in Bauxite.
The atomic number of Aluminum is 13.