Physical Science Unit 1 Chapter 1 Ch 1 - The Nature of Science Based on: Glencoe Physical Science 2008

Chapter One 1 - Section 1 The Methods of Science Science studies the natural world. It comes from a word meaning “knowledge”. Science is a process where questions are asked and we try to explain why things are the way they are. They question things about the natural world. [NOT supernatural!]

Three main categories of science: life science studies living things (biology) Earth science studies earth and space physical science studies matter and energy sometimes a scientific study will overlap the categories

Science explains the natural world; explanations can change over time. Ex: how atoms are thought to look like JJ Thomson – plum pudding Rutherford – planetary Present day – many scientists – electron cloud Scientists investigate nature by observation and experimentation Making models

Scientific Method Scientific method - organized set of investigation procedures There are 7 steps. 1. State a problem. Why does this happen? How does this happen. 2. Research what is already known and Gather new information and observations. 3. Form a hypothesis or educated guess based on knowledge and observation. * The best definition for hypothesis is a “Testable Prediction”.

Scientific Method 4. Test a hypothesis using an experiment. The experiment must have variables, a constant, and a control 5. Analyze data from an experiment or investigation. 6. Form a conclusion based on the data. 7. Be objective. This means be open-mindied and accept all results. Reduce bias (favoring a certain answer) by keeping accurate records, using measurable data, and repeating the experiment.

An experiment must have each: a. An independent (manipulated) variable is what you plan to change to determine how it will affect the dependent variable. b. A dependent (responding) variable changes value as other variables change. It depends on the other variables. c. A factor that does not change when other variables change is a constant. d. A control group is the standard to which test results can be compared.

Joey wants to see how salt affects the boiling temperature of water. He plans to add 5 grams of salt to 100mL of water and then measure its boiling point. Then he adds a total of 10 grams of salt to the same 100 mL of water and measures it boiling point. Then he adds a total of 15 grams of a salt to the same 100 mL of water and measures the boiling point. What is the independent variable? What is the dependent variable? What is the control? What is constant?

Ch 1 Sect 1 continued …. Models represent ideas, events, or objects and can be physical or computerized. Example: the model of the atom A theory is an explanation based on many observations and investigations (* that has never yet be proven to be false – never yet “falsified”) A scientific law is a statement about something that always seems to be true. (* but could one day be falsified simply by one negative test) Science deals with the natural world; questions of value or emotion cannot be answered. Technology - applied science helping people

Discussion Questions What does “science” mean? What area of questioning is science restricted to? How many steps are in the scientific method? What are they? What do they mean? What are the types of variables in an experiment? What do they mean? What does it mean to be objective? What is a bias? Why is supernatural stuff not considered “science”?

Do NOT Believe Anything I say, or . . . Anything anyone else might say. Unless there is sufficient EVIDENCE to make it worthy of your trust (faith, belief). Sid Galloway www.soulcare.org

Ch 1 Section 2 Standards of Measurement A. Standard - exact quantity that people agree to use for comparison. A “unit” is a standard. Ex: METER B. Measurements must have a number and a unit. 1. SI - an improved version of the metric system used and understood by scientists worldwide. Comes from a French phrase for “international system” 2. SI system is based on multiples of 10 and uses prefixes to indicate a specific multiple.

SI Units SYSTEME INTERNATIONAL d'UNITES (INTERNATIONAL SYSTEM OF MEASUREMENTS) The SI is a Universal, Standardized form of measurement that is use by all scientists around the world.  It allows us to understand each others work and duplicate each others experiments to check the results. Sid Galloway www.soulcare.org

SI BASE UNITS: There are SEVEN Fundamental Base Units quantitiy unit abbreviation Length - meter m Mass - kilogram kg Time - second s Electric Current - ampere A Temperature - kelvin K Substance Amount - mole mol Luminosity - candela cd Sid Galloway www.soulcare.org

Measurements: SI quantities, units, symbols Length is measured using a unit appropriate for the distance between two points. Unit is meter (m) Mass - measure of matter in an object. Unit is gram (g) Time is the interval between two events. Unit is second (s) [sometimes (sec) is also used] Temperature is measured using a thermometer. Units are degrees Fahrenheit or degrees Celsius. SI unit is Kelvin

Derived units A unit obtained by combining different SI units is called a derived unit. It can be made by combining SI base units. Common quantities measured in derived units: Volume – the amount of space an object occupies. Measured by length x width x height. Units can be in3 or ft3 or cm3. Most common is dm3 which is same as is Liter (L) Density - mass per unit volume of a material. Units are gram/milliliter (g/mL) Speed – distance divided by time (m/s)

Volume Visualized

Converting between SI units and between SI and English units To convert, multiply by a “conversion factor” where the top equals the bottom Ex: Convert 32 inches to feet: Ex: Convert 21 pints to quarts: Ex: Convert 58 mL to L

More examples:

Temperature The Kelvin scale is the SI temperature scale, and the SI unit of temperature is the kelvin (K). Historically, the Kelvin scale was based on the properties of gases …. Zero on this scale is the lowest attainable temperature, a temperature referred to as absolute zero. Both the Celsius and Kelvin scales have equal-sized units—that is, a kelvin is the same size as a degree Celsius. the Kelvin and Celsius and Fahrenheit scales are related as follows: Kelvin = C + 273 C = Kelvin – 273 F = (C x 1.8) + 32 C = (F – 32) / 1.8

Temperature

Temperature conversions: Convert: 98. 6 degrees F to C 20 degrees C to F 300 Kelvin to C -10 degrees C to Kelvin 68 degrees F to Kelvin

SI Unit Prefixes

Discussion Question What is the SI measurement system? An improved version of the metric system used by scientists worldwide

Chapter 1 Section 3 Communicating with Graphs A. Graph - visual display of information or data that is used to detect patterns B. A line graph shows a relationship where the dependent variable changes due to a change in the independent variable. 1. The scale should make the graph readable. 2. The x-axis should always be used for the independent variable. 3. Units of measurement must be consistent. C. Bar graphs compare information collected by counting. D. Circle graphs show how a whole is broken into parts.

Discussion Question What axis should always be used for the independent variable? The x-axis

Section 4 – Technology Technology – application of scientific knowledge to benefit people Technology can be: Human made (ex – computer) Methods or techniques ( process of making a computer) Knowledge or skills (skill to use a computer) System of people and objects (the internet)

Global technology Developing countries need different technologies than developed ones How are the needs of Haiti different than those of the US? The US is an industrialized country; we have safe water, clean air, lots of food, phones, etc

Social forces Society is a group of people with similar beliefs and values. The driving force of many inventions is personal wants and needs.

Economic forces Governments supply funding to improve technology Private foundations supply some funding Private industries supply funding for research

Morals and ethics Much science and research come under fire for being “bad” or “immoral”. Examples:

Hypothesis Meters Problem Experiments Grams Kelvins Seconds