8/11/2015 PHYSICAL SCIENCE 1.1 WHAT IS SCIENCE? BIG IDEAS OF PHYSICAL SCIENCE BRANCHES OF SCIENCE WHAT IS SCIENCE?

Transcription

1 PHYSICAL SCIENCE Chapter 1 Science Skills GOAL: Students will be able to distinguish what characterizes science and its methods. Standard: SC.912.N.1.2, SC.912.N.1.3, SC.912.N.1.4, SC.912.N.1.5, SC.912.N.1.6, SC.912.N.1.7, SC.912.N.2.1, SC.912.N.2.3, SC.912.N.2.4, SC.912.N.2.4, SC.912.N.2.4, SC.912.N.2.5, SC.912.N.4.1, & SC.912.N.4.2 Students will: Level Scale 4 Generate and their own scientific study using the scientific method and generate tables, graphs, and figures to explain their scientific data. 3 distinguish what characterizes science and its methods through empirical observations testable questions hypotheses experiments logical reasoning coherent theoretical constructs 2 illustrate the strength of a scientific claim by critical and logical thinking. 1 identify sources of information and assess their reliability. 1.1 WHAT IS SCIENCE? Science is a system of knowledge and the methods you use to find that knowledge Science begins with curiosity and often ends with discovery Technology is the use of knowledge to solve practical problems. Science and technology are interdependent. Advances in one lead to advances in the other WHAT IS SCIENCE? Scientists Are curious Ask questions about how the world works Seek answers Does the radiation released by cell phones cause brain tumors? BRANCHES OF SCIENCE Physical Science Physics BIG IDEAS OF PHYSICAL SCIENCE Chemistry Natural Science Earth and Space Science Geology Meteorology Oceanography Astronomy 1. Space and Time: Universe is both very old and big 2. Matter and Change: Matter has volume and mass, the building block of matter is atoms 3. Forces and Motion: Force causes change in motion 4. Energy: Kinetic-moving Potential-stored Botany Zoology Life Science Ecology 1

2 1.2 USING A SCIENTIFIC APPROACH THINKING LIKE A SCIENTIST: HOW TO USE THE SCIENTIFIC METHOD Scientific method- An organized plan for gathering, organizing, and communicating information The goal of any scientific method is to solve a problem or to better understand an observed event Steps include: 1. Observation: info obtained through senses 2. Hypothesis: proposed answer to a question 3. Prediction: What you think will take place 4. Experimentation: Controlled Experiment-1 variable (manipulated variable) is deliberately changed 5. Conclusion: Look at data to draw Look for interesting patterns or cause-and-effect relationships. STEP 1: MAKE OBSERVATIONS STEP 2: FORMULATE A HYPOTHESIS A proposed explanation for observed phenomena DEVISING TESTABLE PREDICTIONS We can only evaluate the validity of a hypothesis by putting it to the test. Researchers often pose a hypothesis as a negative statement, proposing that there is no relationship between two factors. THE NULL HYPOTHESIS A negative statement that proposes that there is no relationship between two factors These hypotheses are equally valid but are easier to disprove. An alternative hypothesis It is impossible to prove a hypothesis is absolutely and permanently true. 2

3 HYPOTHESIS: ECHINACEA REDUCES THE DURATION AND SEVERITY OF THE SYMPTOMS OF THE COMMON COLD. STEP 3: DEVISE A TESTABLE PREDICTION Suggest that under certain conditions we will make certain observations. Keep in mind any one of several possible explanations could be true. STEP 4: CONDUCT A CRITICAL EXPERIMENT an experiment that makes it possible to decisively determine whether a particular hypothesis is correct STEP 5: DRAW CONCLUSIONS, MAKE REVISIONS. Trial and error Making revisions WHEN DO HYPOTHESES BECOME THEORIES? In the context of science, a theory is Broader in scope than a hypothesis General enough to lead to new testable hypotheses Supported by a large body of evidence in comparison to a hypothesis A scientific theory is a well tested explanation for a set of observations EX: Kinetic theory of matter says all particles of matter are in constant motion Scientific law is a statement that summarizes a pattern found in nature EX: Newton s law of gravity states 2 objects are attracted to each other by gravitational force Laws don t attempt to explain patterns in nature, theories do 3

4 CONTROLLING VARIABLES MAKES EXPERIMENTS MORE POWERFUL. 1. Treatment any experimental condition applied to individuals 2. Experimental group a group of individuals who are exposed to a particular treatment 3. Control group a group of individuals who are treated identically to the experimental group with the one exception: they are not exposed to the treatment 4. variables characteristics of your experimental system that are subject to change Ex: manipulated vs responding THE PLACEBO EFFECT EXPERIMENTAL DESIGNS The phenomenon in which people respond favorably to any treatment The placebo effect highlights the need for comparison of treatment effects with an appropriate control group. Blind experimental design The experimental subjects do not know which treatment (if any) they are receiving. Double-blind experimental design Neither the experimental subjects nor the experimenter know which treatment the subject is receiving. HALLMARKS OF AN EXTREMELY WELL-DESIGNED EXPERIMENT Blind/double-blind strategies VISUAL DISPLAYS OF DATA CAN HELP US UNDERSTAND AND EXPLAIN PHENOMENA. Randomized The subjects are randomly assigned into experimental and control groups. 4

5 VARIABLES Independent Variables some measurable entity that is available at the start of a process and whose value can be changed as required. Dependent Variables created by the process being observed and whose value cannot be controlled. STATISTICS CAN HELP US IN MAKING DECISIONS A set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather. Drawing conclusions based on limited observations is risky. Measuring a greater number of people will generally help us draw more accurate conclusions about human height. STATISTICS CAN ALSO HELP US TO IDENTIFY RELATIONSHIPS (OR THE LACK OF RELATIONSHIPS) BETWEEN VARIABLES. a positive correlation meaning that when one variable increases, so does the other PSEUDOSCIENCE AND MISLEADING ANECDOTAL EVIDENCE CAN OBSCURE THE TRUTH 1. Pseudoscience: individuals make scientific-sounding claims that are not supported by trustworthy, methodical scientific studies. 2. Anecdotal observations: based on only one or a few observations, people conclude that there is or is not a link between two things. 5

6 ANECDOTAL OBSERVATIONS do not include a sufficiently large and representative set of observations of the world data are more reliable than anecdotes 1.3 MEASUREMENT SI UNITS OF MEASUREMENT Scientific Notation- way of expressing a value as the product between 1 and 10 and a power of 10 For example 300,000,000 is written 3.0 X 10 8 Makes very large or small numbers easier to work with When multiplying numbers written in scientific notation, you multiply the numbers that appear before the multiplication signs and ADD the exponents Scientists use a set of measuring units called the SI or the International System of Units Revision of the metric system SI BASE UNITS Quantity Unit Symbol Length Meter m Mass Kilogram kg Temperature Kelvin K Time Second s Amount of substance Mole mol Electric current Ampere A Luminous intensity Candela cd DERIVED UNITS Quantity Unit Symbol Area Square meter m 2 Volume Cubic meter m 3 Density Kilograms per cubic meter kg/m 3 Pressure Pascal (kg/m.s 2 ) Pa Energy Joule (k. m2/s 2 ) J Frequency Hertz (1/s) Hz Electric charge Coulomb (A.s) C 6

7 SI PREFIXES Prefix Symbol Meaning Multiply Unity by Giga- G Billion (10 9 ) 1, 000, 000, 000 Mega- M Million (10 6 ) 1, 000, 000 Kilo- k thousand (10 3) 1000 deci- d tenth (10-1 ) 0.1 centi- c hundredth (10-2 ) 0.01 milli- m thousandth (10-3 ) micro- µ millionth (10-6 ) BASE UNITS Length- straight line distance between 2 points Mass- quantity of matter in an object Volume- amount of space take up by an object Density- ratio of an object s mass to its volume nano- n billionth (10-9 ) CONVERSION FACTOR LIMITS OF MEASUREMENT Ratio of equivalent measurements that is used to convert a quantity expressed in one unit to another unit Convert the height of Mt. Everest, 8848 meters into kilometers Precision- gauge of how exact a measurement is The precision of a calculated answer is limited by the least precise measurement used in the calculation Accuracy- closeness of a measurement to the actual value of what is being measured MEASURING TEMPERATURE 1.4 PRESENTING SCIENTIFIC DATA Thermometer Fahrenheit Celsius Kelvin Fahrenheit Celsius Kelvin Water boils Human body Average room Water freezes Scientists organize their data by using data tables and graphs. Data Tables Line Graphs Slope= rise/run Direct proportion Inverse proportion Bar Graphs Circle/Pie Graphs Scientists can communicate results by writing in scientific journals or speaking at conferences 7