Table of Contents 8th Grade Science Class Left side items Page Right side items Table of Contents 1 2 3 Kaleidoscope Analysis 4 Kaleidoscope Lab 5 6 Kaleidoscope Lab Part 2 7 Engineering Design Project Ideas 8 Engineering Design Project Egg Drop 9 Parts of an Experiment – Graphic Organizers 10 Part of an Experiment 11 Obscertainer Lab Analysis 12 Intro to Atomic Theory “Seeing the Un-seeable” 13 14 Atomic Theory Notes 15

EQ: Why Do Theories Change Over Time Questions How Scientists Learned About the Atom Pre-assessment: (answer as a complete sentence) 1) Is it easy or hard to study atoms? Why? It is difficult to study atoms because … 2) What instruments do scientists use to study atoms? Scientists use _______________ and __________ to study atoms. 3) Draw your idea of what an atom looks like. Label any parts you can. 4) How do you think scientists “see inside” atoms? 5) List any facts you know about the atom. ____________________________________________________ How do we study what we cant see with our own eyes? Activity 1: Paper Cut Activity 2: Obscertainer Trial 1 Trial 2 Actual

What was difficult about the obscertainer lab? What would you do differently if you repeated the lab? Would you use other materials? Did you get them all right?

What does an atom look like? How did scientists figure out what it looks like?

EQ: Why Do Theories Change Over Time? What Does an Atom Look Like? Questions Scientist Atomic Theory Picture

The atomic model has changed throughout the centuries, starting in 400 BC, when people thought it looked like a ball → A model uses familiar ideas to explain unfamiliar facts observed in nature. A model can be changed as new information is collected.

Democritus Smallest piece of all matter is not divisible He named the smallest piece of matter “atomos,” meaning “not to be cut.”

Atomos To Democritus, atoms were small, hard particles that were all made of the same material but were different shapes and sizes.

Atomic Theory

John Dalton 1760-1844 Father of Modern Atomic Theory matter is made of atoms atoms in an element are identical different elements have different atoms atoms maintain their mass even in a chemical reaction

J.J. Thomson 1897

When a magnet was placed near the beam of light, it separated into two parts

When a magnet was placed near the beam of light, it separated into two parts

Thomson Model Where did the negative charges come from? This surprised Thomson, because the atoms of the gas were uncharged. Where had the negative charges come from?

Thomson Model Proposed a model of the atom that is sometimes called the “Plum Pudding” model. A small particle with negatively charged electrons scattered around.

J.J. Thomson 1897 discovered electrons (charged particles)