Explanation

• Nicolaus Copernicus proposed the heliocentric model.
• Heliocentric means the Sun is at the center.
• Earth and other planets revolve around the Sun.
• Proposed in the 16th century.
• Ptolemy supported the geocentric model (Earth-centered).

Explanation

• A Barometer is an instrument used to measure air (atmospheric) pressure.
• It helps in weather forecasting by measuring changes in atmospheric pressure.
• The mercury barometer is the oldest type of barometer.
• It was invented by Evangelista Torricelli in 1643.
• Barometers are widely used in meteorology and aviation.

Last verified on 09-07-2026

Explanation

• Heinrich Wilhelm Waldeyer coined the word "neuron" in 1891.
• He based it on the ancient Greek word for sinew or cord.
  
• Neuron theory/doctrine emerged at the end of the 19th century.
• Core claim — Nerve tissue = individual cells; each is a genetic, anatomic, functional, and trophic unit.
  
  Last updated by NA on 09-09-2026

Explanation

• Jabir ibn Hayyan, known as the "father of chemistry."
• He was an Arab Chemist.
• Composition of Alchemy was written by Jabir Bin Hayyan.

Notable ideas:

• Use of organic substances in chemistry
• Sulfur-mercury theory of metals
• Science of the balance
• Science of artificial generation

Last verified on 07-02-2026

Explanation

• Sir Isaac Newton formulated the Three Laws of Motion.
• He presented them in 1687 in his famous work Principia Mathematica.

Three Laws of Motion:

1. First Law — Law of Inertia: An object remains at rest or in uniform motion unless acted upon by an external force.
2. Second Law — Law of Acceleration: The net force on an object is related to its mass and acceleration.
3. Third Law — Action and Reaction: For every action, there is an equal and opposite reaction.

Last verified on 05-09-2026