chapter 1 power point

CHAPTER ONE

SCIENCE SKILLS

WHAT IS SCIENCE?

It is a knowledge and the process that gets us to that knowledge.

If it begins with curiosity- it ends in discovery.

The fun part of science is that you don’t know what you will find.

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Curiosity provides questions.

Methods such as observing and measuring provide ways to find answers.

WHAT IS TECHNOLOGY?

It improves people’s lives . The use of knowledge (science) to solve practical problems.

Advances in one lead to advances in the other (interdependent)

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The goal of science is to expand knowledge. The goal of technology is to apply that knowledge.

LAB REVIEW

Inquiry Activity P. 1- How do scientist use their observations/

Solution: CuCl2

Copper(II) chloride + Aluminum →Copper +Aluminum chloride

A single replacement reaction is what occurred in the lab.

The aluminum replaced the copper in the solution.

SECTION 1.1 INTEREST GRABBER (JOURNAL ENTRY)

Science improves our Quality of Life. Advances in science have led to devices that make our lives easier and more pleasant. For example, the microwave oven makes it possible to prepare meals and snacks in minutes rather than hours.

1. Name five household devices that make your life easier or more pleasant.

2. Go through your list and describe how each device's function was accomplished before its invention.

BRANCHES OF SCIENCE

The study of science is broken down into social sciences and natural science.

Natural science is usually divided into 3 branches.

1: PHYSICAL SCIENCE

Focus on non-living things

A. Physics-The study of matter and energy and the interactions between the two through forces and motion

B. Chemistry- The study of composition, structure, properties, and reactions of matter.

2: EARTH AND SPACE SCIENCE

A. Geology-(Earth science)The study of the origin, history, and structure of Earth.

B. Astronomy-(Space science) The study of the universe beyond Earth, including the sun, moon, planets, and stars.

3: LIFE SCIENCE

The study of living things.

A. Biology- The study of life and life processes.

SECTION 1.2 USING A SCIENTIFIC APPROACH

Scientific Method- An organized plan for gathering information.

Goal- to solve a problem or to better understand an observed event.

STEPS TO THE SCIENTIFIC METHOD

Make an observation

Ask a question

Develop a hypothesis

Test hypothesis with an experiment

Test with more experiments Revise hypothesis

Analyze data and draw conclusions

Hypothesis is supported Hypothesis is not supported

Develop a theory

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1. Observation- information that you gain through your senses.

- Repeatable observations are known as facts.

2. Hypothesis- is a proposed answer to a question.

- has to be testable

- can be an if, than statements.

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3. Experiments- used to test hypothesis.

- Any factor that can change in an experiment us called a variable.

- Manipulated variable- the variable that causes a change in another variable.

- Responding variable- the variable that changes in response to the manipulated variable.

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A controlled experiment is an experiment in which only one variable, the manipulated variable, is deliberately changed at a time.

- It exams the relationship between the manipulated and responding variables.

- Controlled variables- all variables being held constant.

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4. Analyze data and draw conclusions

Based on the data produced by an experiment, scientists can draw a conclusion about whether the evidence supports or disproves the hypothesis.

Once a hypothesis has been supported in repeated experiments, scientists can begin to develop a theory.

A scientific theory -is a well-tested explanation for a set of observations or experimental results.

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Theories are never proved.

- They may be revised or replaced.

Scientific law- A statement that summarizes a pattern found in nature.

* A scientific law describes an observed pattern in nature without attempting to explain it. The explanation of such a pattern is provided by a scientific theory.

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A model is a representation of an object or event.

Scientific models make it easier to understand things that might be too difficult to observe directly.

Communication- this is done throughout the process.

SAFETY IN THE LAB

Whenever you work in your science laboratory, it’s important to follow safety precautions at all times.

Always follow your teacher’s instructions and the textbook directions exactly.

SECTION 1.3 MEASUREMENT

• Scientist often work with very large or very small numbers.

• Instead of writing out all the zeroes in such numbers, you can use a shortcut called scientific notation.

• Scientific, notation is a way of expressing a value as a product of a number between 1 and 10 and a power of 10.

• For example, the number 300,000,000 written in scientific notation is 3.0 x 10 8

• Using scientific notation makes very large or very small numbers easier to work with.

SI UNITS

Scientists use a set of measuring units called SI, or the International System of Units.

SI is built on seven metric units, know as base units.

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1. The meter [m] for length

2. The kilogram [kg] for mass

3. The kelvin[K] for temperature

4. The second[s] for time

5. The mole [mol] for amount of substance

6. The ampere [A] for electric current

7. The candela [cd] for luminous intensity

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Additional SI units, including volume and density, are derived units.

Derived units are made from combinations of base units.

Density- is the ratio of an object’s mass to its volume.

Density= Mass = M units are g/L

Volume V

METRIC PREFIXES

The unit for a given quantity is not always a convenient one to use.

The measurement can be written in a more compact way using a metric prefix.

A metric prefix indicates how many times a unit should be multiplied or divided by 10.

Chart on page 17

FACTOR LABEL METHOD

Easiest way to convert from one unit of measurement to another is to use conversion factors.

Example: kilograms to pounds

- Use the conversion 2.1kg = 1lb

-It is a ratio of equivalent measurements that is used to convert a quantity from one unit to another.

LIMITS OF MEASUREMENTSPrecision is an assessment of how exact a measurement is.

Significant figures are all the digits that are known in a measurement, plus the last digit that is estimated.

The fewer the significant figures, the less precise the measurement is.

The precision of a calculated answer is limited by the least precise measurement used in the calculation.

Another important quality of measurement is accuracy, which is the closeness of a measurement to actual value of what is being measured.

RULES FOR SIGNATURE FIGURES

1) Digits other than 0 are always significant

Example

96 = 2 significant numbers

0.52 = 2 significant numbers


2) 1 or more final zeros used after the decimal point are always significant.

Example

4.00= 3 significant figures - it is an exact measurement.

0.520 = 3 significant figures (sig Figs)


3)Zeros between two other significant figures (numbers) are always significant.

Example

204 = 3 sig figs.

10.06 = 4 sig figs.

3.040 = 4 sig figs


4) Zeros used solely for spacing the decimal point are not significant. These zero’s are called place holders

Example

400 = 1 sig fig

400. = 3 sig fig

0.002 = 1 sig fig

SIGNIFICANT FIGURES IN CALCULATIONS

Addition and Subtraction

The answer can only have the same number of digits as the measurement with the least number of digits to the right of the decimal place.

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Examples:

Addition Subtraction

6.43 213.67

+2.015 98

8.445 = 8.44 115.67 =116

SIGNIFICANT FIGURES IN CALCULATIONS

Multiplication and Division

The answer can have only the same amount of significant figures as the measurement with the least number of significant figures.

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Examples:

Multiplication Division

12.0 3 sig. figs 2.50 0.04 = 62.5

4.3 2 sig. figs 3 1 = 1

51.6 = 52 answer 2 sig. figsanswer 60 1 sig. fig

TEMPERATURE CONVERSIONS

• We use Kelvin (K) for SI unit

• Do not use a degree mark () before the K.

• We use Celsius (C) for metric system

• We use Fahrenheit (F) in the United States


Conversion Examples:

Formula Example

C + 273.15 = K 25C + 273.15 = 298.15 K

K – 273.15 = C 315.00 – 273.15 = 41.85C


Formula Example

F = 9/5 C + 32 F = 9/5 28C + 32 = 82F

C = 5/9(F – 32) C = 5/9(77F –32) = 25C

9/5 = 1.8

5/9 = 0.55