DATA
Quantitative
Qualitative
INCLUDES A NUMBER
MEASUREMENT
Quantity
Definition
Volume
Measure of the space that matter takes up
Mass
Measure of the amount of matter
Temperature
Measure of average KE (vibration of molecules)
Length
distance between two points
Time
Duration of an event
Energy
The ability to do work
IS A VERBAL DESCRIPTION OF A SUBSTANCE
Unit
L (standard),
mL = cm3
g
Equipment
Beaker, graduated
cylinder
balance
°C, K
thermometer
m, cm, mm
Meter stick or
metric ruler
sec
Joule, Calorie
Examples:
 Round
 Hot
 Color
 Shape
 Size (S, L, M)
stopwatch
calorimeter
READING LAB EQUIPEMENT https://www.youtube.com/watch?v=pFl49nIGQF8
These 3 graduated cylinders have different levels of precision. Indicate which one shows a measurement of 4 mL, 4.3 mL, and 4.35 mL.
1.
2.
3.
4.
5.
6.
7.
8.
9.
#1: 4.3mL
#2: 4.35mL
#3:
4mL
10.
11.
Therefore, graduated cylinder #__2_____ gives us the most precise measurement.
RULE: Always read lab equipment one place value past the decimal value that you see!
Ruler A: is calibrated to the tenths, so you estimate/read the hundredths
Length of nail when measured with Ruler A: : 4.38cm
Ruler B: is calibrated to the ones so you estimate/read to the tenths
Length of nail when measured with Ruler B: 4.4cm
TRY!
A
40 cm
50 cm
B
40 cm
41 cm
Ruler A: is calibrated to the tens so you estimate/read to the ones
Length of the line when measured with Ruler A: 48cm
Ruler B: is calibrated to the ones so you estimate/read to the tenths.
Length of the line when measured with Ruler B: : 40.8cm
TRY READING EQUIPMENTS
Place Value Completely Marked
Off
36
335.3,
Place Value to Estimate(Final answer) : 335.30g
Place Value Completely Marked Off:
*Place Value to Estimate
(Final answer)
36.5mL
SIGNIFICANT DIGITS: Determining Accuracy of Lab Equipment by Evaluating Measurements
All digits that are read or estimated in lab are considered “significant digits”. Any measurement given in a
lab report communicates three things to the reader: the numeric value of the measurement, the degree of
calibration of the equipment and the unit the measurement was taken in.
Here are some examples of determining significant digits from lab measurements:
Measurement
Equipment Read To:
Equipment Calibrated to: # of significant
(includes estimate)
digits
tenths
place
ones
place
14.0g
3
ones
place
tens
place
25mL
2
thousandths
place
hundredths
place
0.035mL
2**
** notice that “place holder” zeros are not actually measured, so are not considered significant digits!
Follow the examples above to complete the chart below:
Measurement
Equipment Read To:
Equipment Calibrated to: # of significant digits
ESTIMATED
233 °C
ones
Tens
3
17.666 g
Thousandths
Hundredths
5
12.1 mL
Tenths
Ones
3
0.00346 cm
Hundred thousandths Ten thousandths
3
920.5 kg
Tenths
Ones
4
0.0250 L
Ten thousandths
Thousandths
3
127 g
13.555cg
Ones
Thousandths
tens
Hundredths
3
5
952m
ones
tens
3
Zeros at the end of numbers without a decimal are difficult to interpret. For example – in the measurement
850mL, it is unclear whether the graduated cylinder was marked off to the hundreds and the fifty was estimated,
or whether it was marked off to the tens, and just happened to be on the line. Because of this, a decimal can be
placed at the end of the number to indicate that the zero was actually measured. Another way to indicate which
zeros were actually read is to draw a line over the last significant zero.
Calibrated to hundreds
Read to tens: 850mL
Measurement
Equipment Read To:
Calibrated to tens
Read to ones: 850. mL or
850mL.
850mL
tens
Equipment
Calibrated to:
hundreds
# of significant
digits
2
850. mL
ones
tens
3
1,200mL
hundreds
thousands
2
1,200 mL
tens
hundreds
3
34000 g
Thousands
Ten thousands
2
Hundreds
Thousands
3
Ones
Tens
5
Tens
Hundreds
4
Tenths
Ones
6
34000 g
34000. g
34000 g
34000.0 g
PRACTICE:
1. Each diagram below represents a piece of lab equipment used to measure liquid volume. Use the
student’s measurement to fill in the calibration boxes.
Student’s measurement =
9
8.7 mL
Equipment Read To: tenths
Equipment Calibrated to: ones
# of significant digits: 2
8
790
Student’s measurement = 787 mL
Equipment Read To:ones
Equipment Calibrated to:
tens
780
# of significant digits: 3
280
Student’s measurement = 27Ō mL
Equipment Read To: ones
Equipment Calibrated to: tens
270
# of significant digits: 3