Evolving Theories of Matter

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Evolving Theories of Matter

Creating a Timeline story of Matter that shows when the key ideas were proposed and who proposed them
Start your timeline at 8000 B.C and add to it as you read through the subsections. Read pages 113-120 of your text

  • For each idea, be sure to include the observations the person made that led to the new theory.

8000B.C Stone Age

Used only simple stone tools at the time

Start and Control fire, learned how to change a range of substances to their advantage (Cooked food, fire-hardened mud bricks, tougher tools)

6000 B.C – 1000 B.C

Materials that had a high value to humans

Gold softness made it easy to shape into detailed designs, form into wire, beat into sheets

Copper-could be used to make pots, coins, tools, and jewelry

Production of bronze
1200 B.C discovered how to extract iron form rocks and turn it into useful material
Iron Age began

Iron with Carbon to produce Steel (Sharper blades, strong armor)

Investigated ways of extracting and using different types of liquids

Juices and oils
2500 years ago Idea that all matter is made up of particles

Rock could be broken into smaller pieces

400 B.C Greek philosopher Democritus used the word atom - Atom means “indivisible”

350 B.C Aristotle, “everything was made of earth, air, fire and water

Next 2000 years

Alchemists (part magician, part scientist)

Performed some of the first chemistry experiments

Many useful tools, beakers and filters, plaster-of-Paris

1597 Andreas Libau first chemistry text ever printed (how to prepare some chemicals)
1660’s Boyle experimented with the behavior of gases; interested in determining the composition of gases and other substances.

Tiny particles existed in various shapes and sizes

1770’s Lavoisier studied chemical interactions
1780’s System for naming chemicals (Hydrogen, Oxygen, and Carbon)

Lavoisier known as the father of modern chemistry

1808 John Dalton -Matter was made up of elements

-First to define an element as a pure substance

-Each element is composed of a particle called atom(identical in mass)

- Billiard ball Model

JJ. Thomson – First to discover a subatomic particle

  • Called them electrons

1897 – Proposed the raisin bun model

-positively charged sphere with negatively charged electrons embedded

-negative electrons balance te positive sphere – so had no charge

- Nagaoka’s model showed the atom as a positive sphere around which electrons orbited in a ring
1909 Rutherford – Proposed atoms were mainly empty space (positive particles could pass) but at the core a tiny positive nucleus
Bohr’s Model - Electrons do not orbit randomly, move in circular orbits (Electon shells)

-electrons jumped between by gaining and losing energy

Chadwick - nucleus contained positively charged particles called protons and neutral particles called Neutrons

Today’s quantum mechanics model describes the atom as a cloud of electrons surrounding a nucleus

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