INFORMATION COLLECT: Pre-lab #2 LAB QUIZ #1 MICROWORLDS – Questions? – Four entries due by end of lab next week

Lab 2: Process and Tools of Scientific Inquiry

Two Approaches to Science DISCOVERY SCIENCE No experiments Based on observations Inductive reasoning – general principles derived from large number of specific observations 3 EXAMPLE: All living things are composed of cells

Two Approaches to Science HYPOTHESIS-BASED SCIENCE Involves carefully planned experiments Based on observations Deductive reasoning – takes a general statement and extrapolates specific results we would expect

Experimental Design – Controlled Experiments VARIABLES: things that might change during the experiment INDEPENDENT VARIABLE: the thing that you are changing on purpose (what you’re testing) DEPENDENT VARIABLE: the thing(s) that you are measuring STANDARDIZED VARIABLES (CONSTANTS): things that are the same between your groups The DEPENDENT VARIABLE depends on the INDEPENDENT VARIABLE The DEPENDENT VARIABLE depends on the INDEPENDENT VARIABLE

Experimental Design – Controlled Experiments CONTROL GROUP (CONTROL TREATMENT): The group you are going to compare to; the one you don’t do anything to EXPERIMENTAL GROUP: The group(s) on which you are testing something

Controlled Experiment Control GroupExperimental Group 7 WATER WATER + FERTILIZER

Only once? How many times should you do an experiment? How should you test multiple samples? 8

Sampling Error Draw 1 jelly bean? Draw 10 beans? Draw 100 beans? Draw all the beans? 9 Starr – Ch 1: Sampling Error Animation

Experimental Design – Controlled Experiments LEVELS OF TREATMENT: The values set for the independent variable REPLICATION: Repeating the experiment numerous times under exactly the same conditions SAMPLE SIZE: More samples are better

Lab: Black Box Experiment Identify what is contained in your box without peeking!

Scientific Notation and the Metric System – Appendix A SCIENTIFIC NOTATION: More compact form of a very large or very small number The distance to the Sun's nearest neighbor Alpha Centauri is greater than 10,000,000,000,000,000 m.

Tools for Scientific Inquiry: Scientific Notation Tells you how many times you must multiply or divide by 10 to get the number A x 10 B The distance to the Sun's nearest neighbor Alpha Centauri is greater than 1 x m.

Tools for Scientific Inquiry: Scientific Notation 1 x  positive number = multiply by x m  negative number = divide by

Tools for Scientific Inquiry: Scientific Notation MULTIPLICATION: Add the exponents EX: (2 x 10 4 )(3 x 10 5 ) = 6 x * = DIVISION: Subtract the exponents EX: (6 x 10 9 ) / (3 x 10 5 ) = 2 x / = 20000

Tools for Scientific Inquiry: The Metric System

This? Or This…. GIGA- MEGA- KILO- BASE UNIT DECI- CENTI- MILLI- MICRO- NANO-

Metric how-to It’s all about powers of TEN

Basic Metric Measurements METER Measure of LENGTH Approximately 1 yard

Basic Metric Measurements GRAM Measure of MASS 28 g = 1 oz

Basic Metric Measurements LITER Measure of VOLUME Slightly larger than 1 quart

Basic Metric Measurements LITER Measure of VOLUME Slightly larger than 1 quart

Metric Prefixes to know PREFIXX Base UnitScientific Notation KILO1000x base1 x10 3 m/km BASE UNITMeter, Liter, Gram1 CENTI1/100; x m/cm MILLI1/1000; x m/mm MICRO1/100000; x m/um NANO1/ ; x m/nm

Converting Units Set up equations to cancel out units 200 m = cm 200 m * 1 x 10 2 cm = cm = 2 x 10 4 cm 1 m THINK ABOUT YOUR ANSWER: Should there be more cm than m? Should there be fewer? DOES YOUR ANSWER MAKE SENSE?? THINK ABOUT YOUR ANSWER: Should there be more cm than m? Should there be fewer? DOES YOUR ANSWER MAKE SENSE??

Converting Units Set up equations to cancel out units kg = ng kg * 1 x 10 3 g = 0.5g * 1 x 10 9 ng = 5 x 10 8 ng 1 kg1g 1 kg THINK ABOUT YOUR ANSWER: Should there be more nm than kg? Should there be fewer? DOES YOUR ANSWER MAKE SENSE?? THINK ABOUT YOUR ANSWER: Should there be more nm than kg? Should there be fewer? DOES YOUR ANSWER MAKE SENSE??

Practice Question 250 cm = Meters? Millimeters?

Basic Metric Measurements CELSIUS Measure of TEMPERATURE Based on the boiling and freezing points of water

Measurements Accurate How close is the measurement to the true value? Precise How consistently can a measurement be reproduced?

Measurements Use a measuring tool that is close to the measurement you want to make

Measurements Use a measuring tool that is close to the measurement you want to make

Lab: Appendix A - Measuring Read the information in the lab Practice measuring with a pipette, graduated cylinder, balance, ruler/meter stick Be able to answer the questions in the Study Guide in preparation for the quiz next week!