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lab significant digits modified

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Measurements and Significant Figures Lab
Purpose: The aim of this lab is to practice recording measurements with the correct number of
significant figures.
Procedure:
1. Several stations have been set up around the room. Step up to a station, read the directions, and read
the measurement according to the directions. Record this measurement with the correct units in the
slot in your data table that corresponds to the station number. Although you and your team mates may
mass the objects together at stations 4, 6, and 7, you must read the instruments yourself and should not
copy a peer's measurement.
Station #
1
Measuring tool
Measurement (with unit)
2
3
4
5
6
7
8
9
10a
10b
10c
11
Discussion and Analysis:
1. Which stations required no approximation of the last significant figure? Why?
2. Did the estimations of you and your group mates always match? Why or why not?
3. Why is it important in lab activities to have one lab partner measure both the beginning and final
measurements for a specific tool?
Station 1: Ruler (less precise)
Directions: Measure the piece of paper in centimeters, being sure to estimate visually the last readable number.
Measure value to the nearest 0.1 cm.
Station 2: Graduated cylinder (big):
Directions: Measure the liquid in the graduated cylinder to the nearest 0.1 mL, being sure to estimate visually the
place after the decimal. Record measurement to the nearest 0.1 mL.
Station 3: Buret:
Directions: Burets are measured from the top down. Be sure to honor this as you read the volume of the liquid
inside to the nearest 0.01 mL. Record this measurement in your table.
Station 4: Triple Beam Balance:
Directions: Adjust the balance to zero if necessary then place the object on the balance and adjust the balance to
accurately read the mass of the piece of metal. Record this measurement to the nearest 0.01 g in your table.
When you finish, remove the object and place the balance back to zero.
Station 5: Graduated cylinder (small):
Directions: Measure the liquid in the graduated cylinder to the nearest 1 mL, being sure to estimate visually the
place after the decimal. Discuss with your partner what each graduated line means before measuring. Record
measurement to the nearest 0.01 mL.
Station 6. Electronic balance:
Directions: Tare the balance to zero, check that the units are in grams and place the object on the balance. When
the measurement on the scale stabilizes, record the mass to the nearest 0.01 g in your data table.
Station 7: Analytical balance:
Directions: With glass doors closed, zero the balance. Open a glass door, place the metal on the balance, close the
door, and record the measurement once it equilibrates in your data table to the nearest 0.001 g. Remove the metal
when you finish and close the glass door.
Station 8: Ruler
Directions: Measure the length of the metal cylinder to the nearest 0.01 cm. Record this measurement under
station 8 in your data table.
Station 9: Ruler
Directions: Measure the diameter of the metal cylinder to the nearest 0.01 cm. Record this measurement in your
data table.
Station 10: Best for liquids
a. Record in your data table which of the three items would be best for measuring 9 mLs of liquid.
b. Record in your data table which of the three items would be best for measuring 26 mLs of liquid.
c. Record in your data table which of the three items would be best for measuring 155 mls of liquid.
Station 11: Thermometer
Directions: Read the temperature of the liquid to the nearest 0.1 degree and record this value in your data table.
Remember that the thermometer must remain in the liquid during the reading for an accurate temperature.
Discussion and Analysis:
1. Which stations required no approximation of the last significant figure? Why?
2. Did the estimations of you and your group mates always match? Why or why not?
3. Why is it important in lab activities to have one lab partner measure both the beginning and final
measurements for a specific tool?
Add or subtract with correct significant figures for the following problems:
3.65
12.9958
- 4.01
4.8
13.64
- 5.53
9.0
4.65
+ 12.839
2.22
16.494
- 1.748
4
3.9
+ 9.00000
90.
4.11
+ 3.84
Multiply or divide with correct significant figures for the following problems:
3.65
x 12.9958
4.8 / 3
9.0
x 4.65
2.22 / 4.5
6
x3
6
x4
20 / 3
11.934 / 3.500
4
x 3.9
90./ 56.4
49482.9422
x 699.938
90.09 / 3.47
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