INTRODUCTION TO SCIENCE CHAPTER 1

THE NATURE OF SCIENCE SECTION 1

WHAT IS SCIENCE? Science is the study of… Everything!! A way of learning about the natural world. Branches of science Life sciences Earth sciences Physical sciences

PHYSICAL SCIENCE Physical Science: The study of matter and energy Matter: the stuff the universe is made out of Energy: ability to do work Two major classes of physical science Chemistry: the study of interactions of matter Physics: the study of motion and energy

SCIENTISTS Scientist: a person who studies, or has expert knowledge of a natural or physical science Scientists use skills such as observing, predicting, planning, and inferring to learn more about the natural world Scientists may perform experiments to find new aspects of the natural world, explain a known phenomenon, check the results of other experiments, or test the predictions of current theories.

THEORIES AND LAWS LAW Law: describes a process in nature that can be tested by repeated experiments Based on facts and have been proven Supported by evidence If not supported by new information, the law is rejected Law of Conservation of Energy THEORY Theory: attempts to explain why these processes and observations are so. Based on observations and can be tested Supported by evidence If new information if discovered, the theory is changed Theory of Evolution

MODELS Model: any representation of an object or a system It can be a smaller or larger version, it can be computer generated, or it can be an idea in your head. Working with models can save time and money.

TECHNOLOGY Technology: the application of science for practical purposes We are surrounded by this daily! Cathode Rays CT Scans

THE WAY SCIENCE WORKS SECTION 2

SCIENTIFIC METHOD Method of organizing information and solving problems 1.Make an observation (use your 5 senses) 2.Ask a question 3.Research 4.Form a hypothesis (predict an outcome) 5.Experiment (test the hypothesis) 6.Analyze your results (record and organize your data) 7.Draw conclusion (was your prediction correct?) 8.Repeat your work and share it with others

SCIENTIFIC METHOD Observation I can’t wake up for school Question How can I get up on time? Research Go to bed earlier, set alarms, less technology before bed Hypothesis If I go to bed earlier, then I will be able to wake up. Experiment Try to go to bed earlier, and record if you get up earlier

SCIENTIFIC METHOD Analyze your results Did it work each day? Draw conclusion Did it work overall? If it worked you confirmed your hypothesis, if it didn’t you proved it wrong Repeat your work and share it with others Mistakes happen, always double check, and then tell someone about your discovery

EXPERIMENT Experiment: a controlled procedure carried out to test a hypothesis Variable: condition or trait you are testing (or changing) Independent variable: this variable DOES NOT change in the experiment Dependent variable: the variable that is changing, or being measured Only ONE variable is tested in an experiment!! Control group: does not receive the variable Experimental group: exposed to the independent variable, then compared to the control group NO EXPERIMENT IS A FAILURE!

DATA Qualitative: data that cannot be measured, it describes a QUALITY The softness of a cat’s fur, the color of the sky Quantitative: data involving number, it shows a QUANTITY The age of your car, the hairs on your head

LAB SAFETY Failure to follow lab safety rules will result in disciplinary consequences

MEASUREMENT Mathematics is the language of science Scientists use the SI system (Systeme International d’Unites) Scientists use it because it is consistent The SI system is based on the metric system and has BASE UNITS of measurement

METRIC SYSTEM Length: distance Base Unit: meter (m) Volume: amount of space something takes up Base Unit: liter (L) Mass: amount of matter in an object (not the same as weight) Base Unit: gram (g) Time: the amount of time something takes Base Unit: second (s) Temperature: how hot or cold something is Base Unit: Celsius (C ° ) or Kelvin (K) Depending on the unit, there will be a prefix paired with a base unit

METRIC SYSTEM Some measurements are too large or small to be measured in meters, liters, or grams To avoid decimals, and a lot of zeroes, prefixes can be added to the base units The prefixes represent multiples of ten Add the prefix symbol to the base unit symbol when writing your unit of measurement kilometer km

METRIC SYSTEM

CONVERSIONS Converting from one metric unit to the other For example, how many meters are in 1 km? Write down - G’’ M’’ k H Da base d c m Put your pencil on the given unit (km) Move the necessary number of spaces to get to the desired unit (m) In this case, 3 to the right G’’ M’’ k H Da base d c m Then move the decimal point from the original quantity the same amount 1 km = 1,000 m

CONVERSIONS 387 g to kg 551 cm to m 398 ml to L 0.57 g to mg cm to km kg 5.51 m l 570 mg.587 km

METRIC RULER 2 3 cm

GRADUATED CYLINDER The water will “grip” to the edges and form a depression in the middle, the lowest point of this curve is the meniscus. Read from the meniscus Always put your head at the same level as the meniscus

ORGANIZING DATA SECTION 3

PRESENTING SCIENTIFIC DATA Scientists do written reports and oral presentations in order to share their results. Organizing data is important to allow easier interpretation Picking the appropriate format makes the data easier to understand

LINE GRAPHS Shows continuous change, and the relationship between two variables The x-axis displays the independent variable The y-axis displays the dependent variable

BAR GRAPHS Show a comparison between similar items or events, or representing a single value for many items

PIE GRAPH Show the parts of a whole

SCIENTIFIC NOTATION Scientific notation is used to express really BIG or SMALL numbers more easily. It is expressed as 2 factors: Factor #1: a number between 1 and 10 Factor #2: a power of ten 6.8 x 10 4 = 68,000 The exponent on 10 tells you the number of places to move to the decimal If the exponent is positive, you move to the right If it is negative, you move to the left

QUICK CONVERSIONS 6.7 X X X X ,100, , X X X X10 3

SIG FIGS SIGNIFICANT FIGURES

WHAT ARE SIG FIGS? I READ IN THE PAPER THAT RANDY LERNER (OWNER OF THE BROWNS) IS WORTH 1.7 BILLION DOLLARS. MYSELF AND A FRIEND BOUGHT 4 TICKETS FOR $ ASSUME RANDY LERNER GETS EVERY PENNY OF THAT AND HASN’T HAD ANOTHER EXPENSE YET, DOES THAT MEAN RANDY LERNER NOW HAS EXACTLY $1,700,000,264.30? OF COURSE NOT, ALL OF THOSE 0’S WERE ACTUALLY NUMBERS THAT WE DIDN’T REPORT BECAUSE WE COULDN’T MEASURE ACCURATELY ENOUGH. THE NUMBER WAS ROUNDED!

THIS IS WHERE SIG FIGS COME INTO PLAY ABSOLUTELY ACCURATE MEASUREMENTS ARE IMPOSSIBLE!!! WE MUST ROUND SOMEWHERE WHEN WE DO CALCULATIONS WITH THESE NUMBERS WE MUST REFLECT HOW ACCURATE OUR INITIAL NUMBERS WERE. A SIGNIFICANT DIGIT MEANS THAT DIGIT WAS ACCURATELY MEASURED AN INSIGNIFICANT DIGIT MEANS THAT DIGIT WAS NOT ACCURATELY MEASURED.

RULES FOR DETERMINING IF A DIGIT IS SIGNIFICANT 1.IF IT IS NOT A ZERO, IT IS SIGNIFICANT IF A ZERO IS BETWEEN TWO SIGNIFICANT DIGITS, IT IS SIGNIFICANT ZEROS AT THE END OF A NUMBER WITH A DECIMAL POINT ARE SIGNIFICANT ZEROS AT THE END OF A NUMBER THAT DO NOT HAVE A DECIMAL POINT ARE NOT SIGNIFICANT ZEROS AT THE FRONT OF A DECIMAL ARE NOT SIGNIFICANT

DETERMINE HOW MANY SIG FIGS ARE IN EACH NUMBER ,

ROUND EACH NUMBER TO THE GIVEN NUMBER OF SIG FIGS (2) 734 (4) (3) (5) (4) (3) (5) (3)

HOW TO REPORT ANSWERS WHEN MULTIPLYING OR DIVIDING. YOU CAN ONLY HAVE AS MANY SIG FIGS IN YOUR ANSWER AS YOU DO IN THE NUMBER WITH THE LEAST AMOUNT OF SIG FIGS X 2.1= (2 SIG FIGS) WHEN ADDING OR SUBTRACTING. NUMBERS ADDED TO OR SUBTRACTED FROM INSIGNIFICANT NUMBERS ARE INSIGNIFICANT (ROUNDED OFF) insignificant