Lesson 2Lesson 2

Science & ChemistryScience & Chemistry

Anything in black letters = write it in your notes (‘knowts’)

Why Study Chemistry?

1. Explain the natural world

2. Prepare for a career

3. Be an informed citizen

Technology -

The knowledge and skills available to a society.

Science -

Method of finding out about the world, based on experiment.

Research without a specific application in mind; “just want to know”

Pure Science -

Determining the chemical structure of silk.

Research directed toward a practical goal or application.

Applied Science -

Developing a synthetic chemical with silk-like properties..

Chemistry -

Study of the properties and changes of matter.

Hypothesis -

A proposed explanation for an observation; must be testable

Experiment -

Procedure used to test a hypothesis

Variables -

Factors that may change in an experiment

Independent Variable -

Variable changed on purpose; manipulated

Dependent Variable -

Variable that is observed; responding

Model - Represents an object or event; all models have some flaws.

This is a model of an atom…atoms are not really like this…but it helps

explain and visualize.

What are some things wrong with the model of the solar system?

Theory -

Well-tested explanation; can’t be proven right, could be proven wrong.

What are some theories you’ve heard of?

Atomic Theory Cell Theory

Big Bang Theory Quantum Theory

Theory of Evolution Theory of Plate Tectonics

Supply & Demand Theory Global Warming

A theory is not just a hunch…theories are the best working explanations that we have.

Theories are not guesses, they make testable predictions that confirm their reality.

“Oh… that’s just a theory.”

Law - Fundamental rule that can’t be broken.

What are some scientific laws you’ve heard of?

Laws of Motion

Laws of Thermodynamics

Law of Gravity

Gas Laws (Boyle’s & Charles’s etc)

Antoine Lavoisier (late 1700’s)

Disproved the Phlogiston Theory and explained that combustion requires oxygen

Realized the importance of careful mass measurements

in Chemistry

Some materials burn because they contain phlogiston.

Phlogiston is released into the air when material burns.

When air is full of phlogiston (it is “phlogisticated”) and can no longer support combustion (flame goes out).

Major flaw…some materials weigh more after they are burnt.

Wood Ashes + Phlogiston; ashes weigh less…okay…

But…Iron Rust + Phlogiston; rust weighed more than the iron

Long story short…Lavoisier didn’t like the inconsistencies of the phlogiston theory and came up with a better explanation (theory) of combustion and that is how science is supposed to work.

Phlogiston Theory – no longer valid! flow-JISS-tunn

ASSIGNMENT:

Chapter 1 Practice #1

Define these terms…

Hypothesis

Experiment

Theory

Law

Model

Chemistry

True or False…

A well-tested Theory can become a Law.

A Theory can be proven wrong, but can’t be proven right.

Technology has been around long before Science.

The Independent Variable is also called the Responding Variable.

Explain the difference between…

Theory & Law

Independent & Dependent Variable

Technology & Science