WELCOME TO THE LAB!!

INFORMATION Go over Syllabus (brief) Go over MICROWORLDS (brief) – Two entries due by end of 2 nd lab (week 2). – Two entries due by end of 4 th lab (week 4). – These 4 & 6 additional by the end of lab 10. – Samples that may be done today include pond water and algae. Do not use oil today. – Will have some time at the end of most labs.

LAB SAFETY - it’s mostly common sense: THINK ABOUT WHAT YOU ARE DOING BEFORE YOU DO IT!! THINK ABOUT THE CONSEQUENCES!! LISTEN TO SPECIAL INSTRUCTIONS!! Go over safety/disposal stuff. Prelabs (found on my web site) : DO/COLLECT: Pre-lab #1. Normally done as homework & turned in at the start of the lab. Prelab2 due at the start of the next lab.

Lab 1: The Metric System and the Scientific Method

Two Approaches to Science DISCOVERY SCIENCE No experiments Based on observations Inductive reasoning – general principles derived from large number of specific observations 5 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 VARIABLES: things that might change during the experiment INDEPENDENT VARIABLE: what you are changing in the experiment (what you’re testing) DEPENDENT VARIABLE: what you are measuring CONSTANT VARIABLES: 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 You generally have two groups: 1.CONTROL GROUP (CONTROL TREATMENT): The group you are going to compare to; the one you don’t do anything to 2.EXPERIMENTAL GROUP: The group(s) on which you are testing something

Controlled Experiment Control GroupExperimental Group 9 WATER WATER + FERTILIZER

Only once? How many times should you do an experiment? 10

Sampling Error Draw 1 jelly bean? Draw 10 beans? Draw 100 beans? Draw all the beans? SAMPLE SIZE: The number of samples, the more the better 11

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 number 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

Metric System Science uses the metric system. The metric units are: – meter for distance (measurement from one point to another) – liter for volume (ie, the space that 1 liter of water occupies) – gram for mass (weight), – and degree Celsius for temperature. metric units do not advance like English: grain, ounce, pound, ton they advance using prefixes & powers of ten

Metric how to use Not covered well in the manual, it is all about powers of TEN

Metric PrefixMeaning kilo (kilometer, kilogram)1000 meter, liter, gram1 centi (centimeter, centiliter, centigram) 1x10 -2 (1/100 or 0.01) milli (milliliter)1x10 -3 micro (micrometer) 1X10 -6 (distance in microscopes) nano (nanometer) 1X10 -9 (distance in electron microscopes) other prefixes are not commonly usedgiga is used only in gigabytes & in Back To The Future (1.21 jig- ă -w ă ts)

Another way to use metrics is to simply move the decimal to the left when going up the steps and move the decimal to the right when going down the steps. For example, when converting from 9.9 kilograms to grams we are going down 3 steps, so move the decimal three places right or kg = grams

Metric units are convertible. 1 cubic centimeter (or 1 cc) of water is equal to 1 milliliter (ml) which is equal to 1 gram of water at sea level (& 1 BTU rises 1 cc 1°C). This does not work if water is not the material of study! Metric System

Basic Metric Measurements You will measure water in a cylinder, tends to stick to the sides, especially with glass. This makes the meniscus, the boundary between the air and the water, curved. The correct way to read it is to read it from the bottom of the meniscus!

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??

Practice Question 250 cm = Meters? Millimeters?

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 For example, you would want to measure an ice cream bar in grams and an elephant in kilograms and not vc. vs.

Lab: Read the information in the lab Practice measuring with a pipette, graduated cylinder, balance, ruler/meter stick Be able to answer the questions at the end of the lab in preparation for the quiz next week!

Lab: Black Box Experiment Identify what is contained in your box without peeking! Use what is available to you in the lab and the scientific method! Fill in the Black Box Experiment Data Sheet in the lab and write your estimate Check it with me (if incorrect, try making a 2 nd and 3 rd experiment) When done, you may work on Microworlds (w/o using oil!)

What you’re responsible for I AM giving a quiz on the lab next week Questions for the quiz will be pulled from the lab and the study guide. Most labs have questions at the end, I suggest you DO THEM! Lab1 and prelab2 will be turned in at the start of lab2. Other than laba 1 & 10, the labs will not normally be turned in.