1. Early Ideas About Matter Section 4.1
The History of Atoms
Early Ideas About Matter
Section 4.1

2. Bell Work
Read the following paragraph and describe what the main idea is in a least 3 sentences.
The idea that all matter is made up of tiny, indivisible particles, or atoms, is believed to have originated with the Greek philosopher Democritus. He held that, in addition to being too small to be seen, unchangeable, and indestructible, atoms were also completely solid, with no internal structure, and came in an infinite variety of shapes and sizes, which accounted for the different kinds of matter. Color, taste, and other intangible qualities were also thought to be composed of atoms

3. 3 Key Points
Democritus a Greek Philosopher came up with the idea of atoms
Atoms were very small & indestructible
Atoms made up all matter
Which one of these statements is incorrect?

4. OBJECTIVES:
Compare & contrast the atomic models of Aristotle, Democritus, and Dalton
Understand the Law of Conservation of Mass

5. Spi’s & CLE’s:
CLE Compare and contrast historical models of the atom.
SPI Compare and contrast the major models of the atom (e.g., Democritus, Thomson, Rutherford, Bohr, and the quantum mechanical model).
CLE Investigate the characteristic properties of matter.
SPI Distinguish among elements, compounds, solutions, colloids, and suspensions.

6. Key Facts: Most common substances exist as solids, liquids, & gases
Matter can undergo physical/chemical changes
Mixtures are combinations of two or more substances
A compound is a combination of two or more elements.
Elements are made of atoms

7. When did the concept of atoms begin?
Several thousand years ago Greek philosophers began to speculate about the nature of matter.
They formulated explanations based on their life experiences.

8. Which Greek philosophers had ideas about matter?
Democritus: B.C
Aristotle: B.C.

9. What did Democritus think?
Matter is composed of atomos (atoms), which move through empty space.
Atoms are solid, homogeneous, indestructible, and indivisible.
Different kinds of atoms have different shapes and sizes.
Size, shape, and movement of atoms determine the properties of matter.

10. What did Aristotle think?
Empty space can not exist.
Matter is made up of earth, fire, air, and water.

11. Who was John Dalton?
He revised Democritus’ idea based on scientific results(scientific method/experimentation).
He marks the beginning of what would eventually become the “Modern Day Atomic Theory”.

12. John Dalton’s Atomic Thoery
Matter is composed of extremely small particles called atoms.
Atoms are indivisible and indestructible.
Atoms of a given element are the same size, mass, and chemical properties.
Atoms of specific elements are different from those of another element.
Different atoms combine in simple whole- number ratios to form compounds
In a chemical reaction, atoms are separated, combined or rearranged.

13. Check For Understanding: Quick Quiz
Empty space can not exist.
In a chemical reaction, atoms are separated, combined or rearranged.
Matter is composed of atomos
A. Dalton
B. Democritus
C. Aristotle

14. What is the Law of Conservation of Mass?
This law simply states that the mass of the reactants in a chemical equation must equal the mass of the products.
* Hydrogen Molecule + Oxygen Molecule → Water Molecule

15. Homework: Section 4.1 Assessment Page 105; 1-6 Due: MR – Wednesday
TF – Wednesday
EXTRA CREDIT!!!!!
Chapter 4 On-line
Quizzes

16. Create A Graphic Organizer Closure
Compare & Contrast Aristotle, Democritus, and & Dalton’s Ideas About the Atom using a graphic organizer
Dalton
Aristotle
Democritus
Atoms