Evolving Matter Timeline

Events

Stone Age

8000 BC - 6000 BC

Metals were not discovered, stone tools were used.

Fire is started being controlled by people.

Iron Age

1200 BC - 1000 BC

Learnt to product steel.

Sharper and harder tools for hunting.

Air, Water, Earth, Fire

350 BC - 1650

Theory everything was Air, Water, Earth, Fire

Philosopher, Aristotle believed and created this theory

New interests in Atoms

1500 - 1780

People had a greater interest in understanding the nature of matter and change than the alchemists had.

People investigating the world around them became more like scientists today

New interests in Atoms (2)

1660 - 1780

Robert Boyle experimented with the behaviour of gases.

Robert Boyle was convinced that matter was made up of tiny particles.

Chemistry Develops as A New Science

1780 - 1808

Antoine Laurent Lavoisier had developed a system for naming chemicals.

Using his naming system, Lavoisier defined some of the substances discovered to that time, including hydrogen, oxygen, and carbon

An Atomic Theory Takes Shape

1808 - 1897

John Dalton suggested that matter was made up of elements.

He stated that each element is composed of a particle called an atom.

Adding Electrons To The Atomic Model

1808 - 1897

Thomson experimenting with cathode rays, concluded that the rays were made up of streams of negatively charged particles.

He showed that these particles were much smaller in mass than even a hydrogen atom.

Raisin Bun Model

1897 - 1904

Thomson described the atom as a positively charged sphere in which negatively charged electrons were embedded like raisins in a bun.

The negative electrons balance the positive sphere, so the whole atom has no electrical charge

A Canadian Contribution To Atomic Theory

1898 - 1907

Rutherford suggested that atoms were mainly empty space through which the positive particles could pass, but at the core was a tiny positively charged centre.

This he called the nucleus.

Bohr's Model

1922 - 2000

Bohr's theory was that the electrons in the atoms do not just move randomly . They just jumped between shells gaining or loosing their energy.

Through Bohr's work Chadwick discovered that the nucleus contained positively charged particles called protons, and neutral particles called neutrons.

The Modern Age

2000

The current time that we live in.