Chapter 1 Science Skills Chemistry 1

What is Science – 1.1 T/F? Science consissts of unchanging body of known facts. T/F? Science consissts of unchanging body of known facts. T/F? Scientific Laws can change. T/F? Scientific Laws can change. T/F? Theories can change. T/F? Theories can change. How are science and How are science and technology related?

Science From Curiosity 1.1 Led to use of fire, building of tools, and language Led to use of fire, building of tools, and language Science begins with curiosity and often ends with discovery Science begins with curiosity and often ends with discovery Curisosity and scientific experiment Curisosity and scientific experiment

Science Improves Our Quality of Life 1.1 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 branches 3 branches 1. Physical Science Chemistry – study of the composition, structure, properties, and reactions of matter Chemistry – study of the composition, structure, properties, and reactions of matter Physics – study of matter and energy and the interactions between the 2 Physics – study of matter and energy and the interactions between the 2 2. Earth and Space Science Geology – study of the origin, history, and structure of Earth Geology – study of the origin, history, and structure of Earth Astronomy – study of the universe beyond Earth (sun, moon, planets, and stars) Astronomy – study of the universe beyond Earth (sun, moon, planets, and stars) 3. Life Science Biology – study of living things (physics, chemistry, origin and behavior of living things Biology – study of living things (physics, chemistry, origin and behavior of living things OVERLAPING OVERLAPING

The Big Ideas of Physical Science Space and Time Space and Time Universe = very old AND BIG Universe = very old AND BIG 12.7 billion years old 12.7 billion years old 700 million billion billion billion meters in diameter = universe 700 million billion billion billion meters in diameter = universe 12,700,700 meters in diameter = Earth 12,700,700 meters in diameter = Earth

The Big Ideas of Physical Science Continued Matter and Change Matter and Change Small amt of universe is matter Small amt of universe is matter Has volume and mass Has volume and mass Normally liquid, solid, gas Normally liquid, solid, gas Made of atoms Made of atoms Electrons, protons, and neutrons Electrons, protons, and neutrons Forces and Motion Forces and Motion Forces cause changes in motion Forces cause changes in motion

The Big Ideas of Physical Science Continued Energy Energy Kinetic energy – energy in motion Kinetic energy – energy in motion Potential energy – objects moevd against a force Potential energy – objects moevd against a force Matter absorbs and releases energy Matter absorbs and releases energy Can be transferred Can be transferred

Science and Your Perspective Science is both a process and a body of knowledge Science is both a process and a body of knowledge Science is always changing Science is always changing

Using a Scientific Approach 1.2 Design Your Own Experiment Suppose that you want to conduct a test to see which brand of cleanser produces the best results when cleaning a kitchen floor. Think about how you would conduct this test. 1. What materials would you need? 2. What procedure would you follow? 3. How would you determine which cleanser produces the best results?

Scientific Method 1.2 Organized plan for gathering, organizing, and communicating information Organized plan for gathering, organizing, and communicating information Goal: solve a problem or better understand an observed event Goal: solve a problem or better understand an observed event 1. Make observation – information that you obtain thru your senses 2. Form Hypothesis – proposed answer to a question 3. Test Hypothesis – experiment Manipulated variable – IV – causes a change in something else – I CHANGE Manipulated variable – IV – causes a change in something else – I CHANGE Responding Variable – DV – variable that changes b/c of IV Responding Variable – DV – variable that changes b/c of IV Controlled experiment – one variable is changed at a time Controlled experiment – one variable is changed at a time 4. Draw a conclusion If data doesn’t support hypothesis, scientist revises a hypothesis  new test If data doesn’t support hypothesis, scientist revises a hypothesis  new test

Theory vs. Law – 1.2 Theory - well-tested explanation for a set of observations or experimental results Theory - well-tested explanation for a set of observations or experimental results Never proved Never proved Stronger if the facts support them Stronger if the facts support them May be revised or replace May be revised or replace Law – summarizes patterns in nature Law – summarizes patterns in nature Does not explain observation (explanation is provided by theory) Does not explain observation (explanation is provided by theory)

Models – 1.2 Representation of an object Representation of an object Makes things easier to understand Makes things easier to understand May be too difficult to observe May be too difficult to observe Physical Model Physical Model Ex: how Earth rotates on its axis Ex: how Earth rotates on its axis Computer models Computer models Mental model Mental model Ex: comets are like giant snowball, mostly mad of ice Ex: comets are like giant snowball, mostly mad of ice Challenge models to find new data Challenge models to find new data

1.3 Measurement Important in science and everyday life Important in science and everyday life Scientific Notation – way of expressing a value as the product of a number between 1 and 10 and a power of 10 Scientific Notation – way of expressing a value as the product of a number between 1 and 10 and a power of 10 Use with very large or very small numbers Use with very large or very small numbers Numbers less than 1 have a negative exponent Numbers less than 1 have a negative exponent Negative means move the decimal to the left Negative means move the decimal to the left

1.3 Continued… Scientific Notation Multiplying numbers in scientific notation Multiplying numbers in scientific notation 1. Multiply number that appear before the multiplication signs 2. Add the exponents Dividing numbers in scientific notation Dividing numbers in scientific notation 1. Divide the numbers that appear before the exponential term 2. Subtract the exponents Matt Skills problems page 15 Matt Skills problems page 15

1.3 Continued… SI Units of Measurement Number and unit Number and unit International System of Units International System of Units Developed in France in 1791 Developed in France in system of units, scientist can easily interpret another’s measurement 1 system of units, scientist can easily interpret another’s measurement

Continued 1.3 Base Units Base Quantity Base Unit Symbol LengthMeterM MassKilogramKg TimeSecondS TemperatureKelvinK Amount of a substance MoleMol Electric Current AmpereA Luminous Intensity Candelacd

Continued 1.3 Base Units Length – straight-line distance between 2 points Length – straight-line distance between 2 points Mass- quantity of matter in an object Mass- quantity of matter in an object

1.3 Continued Derived Units QuantityUnitSymbol Area Square meter m2m2m2m2 Volume Cubic meter m3m3m3m3 Density Kilograms per cubic meter Kg/m 3 Pressure Pascal (kg/m. s 2 ) Pa Energy Joule (kg. m 2 /m 2 ) J Frequency Hertz (1/s) Hz Electric charge Coulomb (A. s) C

1.3 Continued… Derived Units Combination of base units Combination of base units Volume – the amount of space taken up by an object Volume – the amount of space taken up by an object Density – ratio of an object’s mass to its volume Density – ratio of an object’s mass to its volume Density = mass/volume Density = mass/volume

1.3 Continued… Metric Prefixes Kids Have Dropped Over Dead ConvertingMetrics Kilo Hecto Deca Origin deci Centi Mili Kg hg dag(Dg) g dg cg mg Giga = = G Mega = = M Micro = = u Nano = = n Conversion Factor – ratio expressed in one unit to another unit

1.3 Continued… Precision and Accuracy dictionary definitions do not clearly make the distinction as it is used in the science dictionary definitions do not clearly make the distinction as it is used in the science Accurate - "capable of providing a correct reading or measurement." In physical science = 'correct'. A measurement is accurate if it correctly reflects the size of the thing being measured. Accurate - "capable of providing a correct reading or measurement." In physical science = 'correct'. A measurement is accurate if it correctly reflects the size of the thing being measured. Precise - "exact, as in performance, execution, or amount. "In physical science = "repeatable, reliable, getting the same measurement each time." Precise - "exact, as in performance, execution, or amount. "In physical science = "repeatable, reliable, getting the same measurement each time." We can never make a perfect measurement. The best we can do is to come as close as possible within the limitations of the measuring instruments. We can never make a perfect measurement. The best we can do is to come as close as possible within the limitations of the measuring instruments.

1.3 Continued… Significant Figures All the digits that are known in a measurement, plus the last digit that is estimated All the digits that are known in a measurement, plus the last digit that is estimated The fewer the sig figs, the less precise The fewer the sig figs, the less precise

Measuring Temperature 1.3 Instrument that measures temperature, or how hot an object is Instrument that measures temperature, or how hot an object is Celsius = (5/9)(F – 32) Celsius = (5/9)(F – 32) Fahrenheit = (9/5)(C) + 32 Fahrenheit = (9/5)(C) + 32 Kelvin = C Kelvin = C Read Page 21 Read Page 21

Presenting Scientific Data 1.4 Organizing Data (makes easier to interpret) Organizing Data (makes easier to interpret) Data Tables Data Tables Relates 2 variables (the IV and DV) Relates 2 variables (the IV and DV) Figure 20, page 22 Figure 20, page 22 Line Graphs Line Graphs Useful for showing changes that occur in related variables Useful for showing changes that occur in related variables IV = x-axis – horizontal IV = x-axis – horizontal DV= y-axis – vertical DV= y-axis – vertical

Line Graphs Continued – 1.4 Slope (steepness) = Rise/Run Slope (steepness) = Rise/Run Change in y/Change in x Change in y/Change in x (y 2 -y 1 )/(x 2 -x 1 ) (y 2 -y 1 )/(x 2 -x 1 ) Δy/Δx Δy/Δx Direct Proportion – one increases, the other increases Direct Proportion – one increases, the other increases Ex: double volume = double mass Ex: double volume = double mass Triple volume = triple mass Inverse Proportion – one increases, the other decreases Inverse Proportion – one increases, the other decreases Altitude increases, temperature decreases Altitude increases, temperature decreases

Bar/Circle Graphs – 1.4 Bar Bar Used o compare a set of measurement, amounts, or changes Used o compare a set of measurement, amounts, or changes Easy to see how the data compares to another Easy to see how the data compares to another Circle Circle Shows how something relates to the whole Shows how something relates to the whole

Communicating Data 1.4 Journals, conferences, , web, conversations, science fairs Journals, conferences, , web, conversations, science fairs Peer Review – process when scientist examines other scientists’ work Peer Review – process when scientist examines other scientists’ work Accurate, honest, feedback, Accurate, honest, feedback, Crucial part of any investigation Crucial part of any investigation