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## PowerPoint Slideshow about 'Objectives' - lycoris-rhea

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Section 1 What Is Physics?

Objectives- IdentifyPhysics and describe theactivities and fields that involve the major areas within physics.
- Describethe processes of the scientific method.
- Describehow a controlled experiment can be used to test a hypothesis.

Section 1 What Is Physics?

Section 1 What Is Physics?

Physics- Physicsis a branch of science that involves the study of the physical world around us.
- Attempts to describe nature in an objective way through measurements.
- The goal of physicsis to use a small number of basic concepts, equations,and assumptions to describe the physical world.
- Physics principles can then be used to makepredictions about the world we live in.

Section 1 What Is Physics?

The 7 Branches of Physics- Mechanics

-study of motion and its causes and the

interactions between objects

-ex. falling objects, friction, weight, spinning

objects

- Thermodynamics

-study of heat and temperature

-ex. objects melting and freezing, cooling

engines and machinery, refrigeration

Section 1 What Is Physics?

- Vibrations and Waves

-study of specific types of repetitive motions

-ex. sound, springs, and pendulums

- Optics

-study of light

-ex. mirrors, lenses, color, and astronomy

- Electromagnetism

-study of electricity, magnetism, and light

-ex. electrical charges, circuitry, and magnets

Section 1 What Is Physics?

- Relativity

-the study of particles moving at any speed,

especially very high speeds

-ex. particle collisions, particle accelerators,

and nuclear energy

- Quantum Mechanics

-the behavior of subatomic particles

-ex. the atom and its parts

Section 1 What Is Physics?

The Scientific Method- There is no single procedure that scientists follow in their work. However, there are certain steps common to all good scientific investigations.
- These steps are called thescientific method.

Section 1 What Is Physics?

Steps of the Scientific Method:- Make observations and collect data that lead to a

question.

- Form a hypothesis and test it using a controlled experiment.
- Interpret results and analyze data.

4. State a conclusion.

Section 1 What Is Physics?

Hypotheses- Ahypothesisis an educated guess that is based on prior scientific research or observations and that can be tested.
- The process of simplifying and modeling a situation can help you determine the relevant variables and identify a hypothesis for testing.

Section 1 What Is Physics?

Galileo’s Hypotheses- Before Galileo, scientists believed heavy objects fell more rapidly than light objects.
- Galileo considered the situation shown.
- If the heavy brick falls faster, what would happen if they were tied together?

Section 1 What Is Physics?

Galileo’s Hypothesis- Since the two bricks can’t fall faster and slower than the heavy brick, Galileo concluded the original hypothesis was wrong.
- Galileo’s hypothesis:
- All objects fall at the same rate in the absence of air resistance.

Section 1 What Is Physics?

Controlled Experiments-A hypothesis must be tested in acontrolled

experiment.

-In a controlled experiment, only one factor is

changed, all other factors remain the same and are

called constants.

-Any one factor that can be changed is called a

variable.

-A controlled experiment tests only one factor at a time

by using a comparison of acontrol groupwith an

experimental group.

Section 2 Measurements in Experiments

Chapter 1

Objectives- Listbasic SI units and the quantities they describe.
- Convertmeasurements into scientific notation.
- Distinguishbetween accuracy and precision.
- Usesignificant figures in measurements and calculations.

Section 2 Measurements in Experiments

Chapter 1

- Dimension - the kind of physical quantity being measured
- Examples: length, mass, volume, time, and so on
- Each single dimension is measured in specific units.
- meters, grams, liters, seconds, and so on
- The derived units are combinations of other units.
- m/s, km/hr/s, kg*m/s, and many others
- Scientists use the SI System of Measurement.
- Also known as the Metric System.

Measurements

Section 2 Measurements in Experiments

Chapter 1

SI PrefixesIn SI, units are combined withprefixesthat symbolize certainpowers of 10.The most common prefixes and their symbols are shown in the table.

Section 2 Measurements in Experiments

Chapter 1

SI Unit ConversionA typical bacterium has a mass of about 2.0 fg. Express

this measurement in terms of grams and kilograms.

Given:

mass = 2.0 fg

Unknown:

mass = ? g mass = ? kg

Section 2 Measurements in Experiments

Chapter 1

Sample Problem, continuedBuild conversion factors from the relationships given in

Table 3 of the textbook. Two possibilities are:

Only the first one will cancel the units of femtograms to

give units of grams.

Section 2 Measurements in Experiments

Chapter 1

Sample Problem, continuedTake the previous answer, and use a similar process to

cancel the units of grams to give units of kilograms.

Section 2 Measurements in Experiments

Chapter 1

Unit Conversions- Convert the following:

1523 g to kg

1.523 kg

348 cm to m

3.48 cm

8.34 µm to m

0.00000834 m

Section 2 Measurements in Experiments

Chapter 1

Accuracy and Precision- Accuracyis a description of how close a measurement is to the correct or accepted value of the quantity measured.
- Precisionis the degree of exactness of a measurement.
- A numeric measure of confidence in a measurement or result is known asuncertainty.A lower uncertainty indicates greater confidence.

Section 2 Measurements in Experiments

Chapter 1

Significant Figures- It is important to record theprecision of your measurementsso that other people can understand and interpret your results.
- A common convention used in science to indicate precision is known assignificant figures.
- Significant figuresare those digits in a measurement that are known with certainty plus the first digit that is uncertain.

Section 2 Measurements in Experiments

Chapter 1

Always significant:Nonzero digits and zeros between them:

357 has 3 significant figures

3075 has 4 significant figures

Zeros to the right of a non-zero digit, and right or left of

a written decimal point:

57.00 has 4 significant figures

2.000 000 has 7 significant figures

Section 2 Measurements in Experiments

Chapter 1

Never Significant:Zeros to the right of a non-zero digit, and left of an unwritten decimal point:

100 has only 1 significant figures

25000 has only 2 significant figures

Zeros to the right or left of the decimal point in numbers less than one:

0.892 has only 3 significant figures

0.00046 has only 2 significant figures

Section 2 Measurements in Experiments

Chapter 1

Addition and Subtraction:

The final digit should be in the same place as the leftmost uncertain digit.

213.67 437.234

- 98 +12.5

115.67 449.734

Since the 8 is the leftmost uncertain digit, the answer should be rounded to 116

Sincethe 5 is the leftmost uncertain digit, the answer should be rounded to 449.7

Section 2 Measurements in Experiments

Chapter 1

Multiplication and Division

Round off to the same number of significant figures as in the measurement with the fewest significant figures.

12 cm x 4.3 cm= 51.6 cm2

rounds to 52 cm2

2.50g / 0.04 cm3= 62.5 g/cm3

rounds to 60 g/cm3

Section 3 The Language of Physics

Chapter 1

Objectives- Interpretdata in tables and graphs, and recognize equations that summarize data.
- Distinguishbetween conventions for abbreviating units and quantities.
- Usedimensional analysis to check the validity of equations.
- Performorder-of-magnitude calculations.

Section 3 The Language of Physics

Chapter 1

Tables

-used to organize data into a clear and meaningful

way

A clear trend can be seen in the data. The more time that

passes after each ball is dropped, the farther the ball falls.

Section 3 The Language of Physics

Chapter 1

Graphs-mathematical, like from the previous table, can be

used to create a graph

The shape of the graph provides information about the relationship between time and distance.

Section 3 The Language of Physics

Chapter 1

Equations- Show relationships between variables
- Directly proportional
- Inversely proportional
- Inverse, square relationships
- Describe the model in mathematical terms
- Allow you to solve for unknown quantities

Section 3 The Language of Physics

Chapter 1

Equation from Dropped-Ball Experiment- The Greek letterD(delta) means“change in.”The abbreviationDyindicates thevertical changeina ball’s position from its starting point, andDtindicates thetime elapsed. The 1/2a is the abbreviation for half of the acceleration due to gravity.
- With symbols, the word equation above can be written as follows:

Dy = 1/2a(Dt)2

- This equation allows you toreproduce the graphandmake predictionsabout the change in position for any time.

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