Slide 1

Monday, Sept. 30th: “A” DayTuesday, Oct. 1st: “B” DayAgenda

Lab questions/problems - collect

 Section 2.2: “Studying Matter & Energy”

scientific method, hypothesis, variable, control,theory, law, law of conservation of mass

Scientific Method activity

Serendipitous Discoveries Assignment/library work time

Homework:

Sec 2.2 review, pg. 53: #1-7

Concept Review: “Studying Matter and Energy”

Lab: “Physical and Chemical Change”

Questions/Problems?

Make sure your conclusion questions areanswered fully in complete sentences…

Remember to write your

reflection statement!

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The Scientific Method

Scientific Method: a series of steps followedto solve problems, including collecting data,formulating a hypothesis, testing thehypothesis, and stating conclusions.

The scientific method is NOT a series

of exact steps, but rather a strategy

for drawing sound conclusions.

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Experiments are Part of the ScientificMethod

An experiment is the process by whichscientific ideas are tested.

Scientists are often confronted by situations inwhich their results don’t turn out as expected.

Scientists don’t view these results as failures.

Unexpected results often give scientists asmuch information as expected results do.

Unexpected results are as important asexpected results.

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Scientific Method Activity

Get in groups of 4.

Without opening the bags, use the scientificmethod to see if you can correctly identify thecontents of each bag.

Be quiet so the other groups don’t hear youand record your answers on a piece of paper.

How many processes that are part of thescientific method did you use?

How many items did you identify correctly?

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Scientific Discoveries Can Come FromUnexpected Observations

Some important discoveries anddevelopments have been made simply byaccident.

Teflon was

discovered by chance.

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Scientific Discoveries Can Come FromUnexpected Observations

Teflon is used as a thermal insulation device inclothing, as a component in wall coverings, andas a protective coating on metals, glass, andplastics.

Teflon’s properties of very low chemical reactivityand very low friction make it valuable in theconstruction of artificial joints for human limbs.

Teflon is also used as a

roofing material.

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Scientific Explanations

Hypothesis: a theory or explanation that isbased on observations and that can be tested.

Hypotheses are tested by carrying outexperiments.

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Scientists Must Identify the PossibleVariables

Variable: a factor that could affect the resultsof an experiment.

A scientist changes variables one at a time tosee which variable affects the outcome of anexperiment.

To know if your hypothesis is right, theexperiment must be designed so that eachvariable is tested separately.

Each Variable Must be TestedIndividually

When a variable is kept constant from oneexperiment to the next, the variable is called acontrol and the procedure is called acontrolled experiment.

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Data From Experiments Can Lead to aTheory

Theory: an explanation for somephenomenon that is based on observation,experimentation, and reasoning.

Any hypothesis that withstands repeatedtesting may become part of a theory.

Because theories are explanations, not facts,they can be disproved but can never becompletely proven.

Theories and Laws Have DifferentPurposes

Law: a summary of many experimental resultsand observations; a law tells how things work.

While a theory is an attempt to explain the causeof certain events in the natural world, a scientificlaw describes the events.

A law is a statement or a mathematicalexpression that reliably describes the behavior ofthe natural world.

Theories and Laws Have DifferentPurposes

Law of conservation of mass: the law thatstates that mass cannot be created ordestroyed in ordinary chemical and physicalchanges.

Products of a chemical reaction

have the same mass as the

reactants have.

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Models Can Illustrate theMicroscopic World of Chemistry

Model: a representation of an object, asystem, a process, or an idea.

A model is simpler than the actual thing that ismodeled.

Models can be most useful in understandingwhat is happening at the microscopic level.

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Serendipitous Discoveries Assignment

Your assignment is to research and write a 1page paper about a serendipitous discovery.

The paper can be hand-written or typed, butmust be at least 1 full page in length.

You must use at least 2 sources and thosesources must be listed at the end of the paper.

You will have time today to begin your research.The rest will be completed outside of class.

You will share your finding with the class on theday the paper is due.

Homework

Sec 2.2 Review, pg. 53: #1-7

Work on serendipitous discoveries paper

Concept Review: “Studying Matter and Energy”

Due on day of Chapter 2 test (Oct. 17th/18th)

Next Time:

Section 2.2 quiz

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