MEASUREMENTS & MATH

EXACT NUMBERS! Numbers determined by counting or by definition Ex: 6 apples, 1 teacher 1 inch=2.54 cm

IN SCIENCE… Numbers are based on MEASUREMENTS made in the lab. Our data is only as good as the measurements we make and the instruments we use.

QUALITATIVE DATA Observation that DOES NOT involve a number/measurement EX. Presence of odor, color change

QUANTITATIVE DATA Observation that DOES involve a number/measurement (has magnitude size or amount) Ex. Length, mass, volume

Accuracy: how close a measured value is to the actual (true) value. Precision: how close the measured values are to each other. COPY IN YOUR NOTES!!

ACCURACY VS. PRECISION

SIGNIFICANT FIGURES Shows how PRECISE a measurement is Indicates the QUALITY of the instrument you use (how sensitive or exact) EX. Graduated cylinder vs. beaker

SIG FIG RULES!

COUNTING SIGNIFICANT FIGURES sig figs 2 sig figs 4 sig figs 6 sig figs

SCIENTIFIC NOTATION Used to write really LARGE or really small #’s Why? To save space & time

SCI. NOTATION RULES! Written in the form of m x 10 n m: ≥ 1 AND <10 indicate the number of sig. figs

STEPS OF THE SCIENTIFIC NOTATION Step 1) Determine the sig figs  106,000,000 = 3 sig figs Step 2) Determine the value of M using the sig figs  1.06 (remember this must be between 1 and 10) Step 3) Add the 10’s multiplier  1.06 x 10 n

Step 4) Determine the value of “n” by counting the number of times you move the decimal in the original number to get the value for “M” Step 5) Determine the sign of “n” by looking at the direction that you moved the decimal  Move decimal to left = “n” is positive  Move decimal to right = “n” is negative

NOW GO THE OTHER WAY!! Ex. 1) 7, 801 Ex. 2) x x 10 -4

Ex. 1) 3.1 x 10 4 Ex. 2) 4.08 x ,

SI UNITS OF MEASUREMENT One system for all scientists around the world We must have a standard for comparison length – meter (m) mass – kilogram(kg) time – second (s) volume – liter (L)

SI PREFIXES Added to base units to represent large or smaller quantities SI Prefix Unit Abbreviation Exponential Factor kiloK10 3 hectoh10 2 dekada10 1 BASEm,g,s,L10 0 decid10 -1 centic10 -2 milli m10 -3 King Henry Died By Drinking Chocolate Milk

EXAMPLE 10 g = ____________mg? K h da b d c m 10,000

EXAMPLE 14.6 dL= __________ kL