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 DATAObservation that DOES NOT involve a number/measurement
EX. Presence of odor, color change
QUANTITATIVE DATAObservation 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!!
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
COUNTING SIGNIFICANT FIGURES
5432.1
0.00032
4004
82.0000
10
5 sig figs
2 sig figs
4 sig figs
6 sig figs
STEPS OF THE SCIENTIFIC NOTATION
Step 1) Determine the sig figs106,000,000 = 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 multiplier1.06 x 10n
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 positiveMove decimal to right = “n” is negative
SI UNITS OF MEASUREMENTOne system for all scientists around the
world
We must have a standard for comparisonlength – meter (m)mass – kilogram(kg)time – second (s)volume – liter (L)
SI PREFIXESAdded to base units to represent large or smaller
quantitiesSI Prefix Unit Abbreviation Exponential Factorkilo K 103
hecto h 102
deka da 101
BASE m,g,s,L 100
deci d 10-1
centi c 10-2
milli m 10-3
King Henry Died By Drinking Chocolate Milk