Experiment 2: Measurements
As part of their daily work, scientists must carry out common laboratory procedures, take
measurements, and report their results accurately and clearly. The system of measurement used in
modern science is the metric system. The metric system is a decimal-based system, meaning that
measurements of each type are related by factors of 10.
The metric system has one standard unit for each type of measurement: the standard unit for length
measurement is the meter (m), the unit for mass measurement is the gram (g), and the unit for
volume is the liter (L). When taking measurements of quantities that are significantly larger or
smaller than the standard unit, prefixes are attached in front of the standard unit. The most common
prefixes are list below.
Prefix
kilo
deci
centi
milli
Symbol
k
d
c
m
Meaning
1000
1/10 (0.1)
1/100 (0.01)
1/1000 (0.001)
PROCEDURE
A. Measuring Length
a. Observe the marked lines on a meter stick. Identify the lines that represent centimeters and
millimeters. Record your observations.
Observations (include a drawing, and label the length represented by each line):
b. Estimate the length and width of this paper in centimeters, and record your estimate here:
Estimated
length:__________cm
width: __________cm
. Now, use the meter stick or a ruler to measure the length and width of this paper in cm.
Estimate the last digit if it fells between the lines.
Actual
length:__________cm
width: __________cm
c. Using a piece of string and the meter stick, measure the length of your shoes in centimeters.
Length of shoes:
__________cm
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B. Measuring Volume
a. Remove a test tube from your drawer (do not use the wider test tubes). Fill the tube with DI
water to the rim (almost overflowing). Hold your large (100 mL) graduated cylinder next to
the test tube. Estimate the volume of water in this test tube in milliliters (mL) using the
graduated cylinder for comparison.
Estimated volume
_________mL
Carefully pour the water into the large graduated cylinder (use your dropper to adjust the
volume to the last line). Record the volume.
Actual volume
_________mL (using 100 mL graduated cylinder)
b. Fill the test tube with DI water to the rim again. Pour the water into a medium (50 mL) sized
graduated cylinder. Record the volume reading.
Actual volume
_________mL (using 50 mL graduated cylinder)
c. Repeat this process using a small (10 mL) graduated cylinder. You must do this in several
steps, by first transferring no more than 10 mL of water to the graduated cylinder at a time,
and then pouring the water into the sink. When you are done, obtain the volume by adding
the total volume measured. Tip:pour about 9 mL of water into the cylinder, then use your
dropper to transfer enough water to exactly match the 10 mL line. This will give you the
most accurate results.
Actual volume
_________mL (using 10 mL graduated cylinder)
(Calculations)
d. Obtain a plastic gallon jug and a large 1L graduated cylinder from the cart. Fill the
graduated cylinder with tap water to the 1 Liter mark. Estimate how many liters are in one
gallon, and write down this value.
Estimated volume
_________L (your estimate does not need to be a whole number!)
e. Carefully pour the water from the graduated cylinder into the gallon jug. Continue to refill
the graduated cylinder with water and pour water into the gallon jug until a total of one
gallon of water has been added. From this, determine how many liters are in a gallon. Have
the instructor initial your results.
Actual volume
_________L
Instructor Initial: ___________
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C. Measuring Mass
a. After your instructor shows you how to use a laboratory balance, determine the mass of a 50mL beaker, a stopper (on cart), and a metal disk (also on the cart). Copy the number or letter
on the disc on your report sheet (if there is one) You must always record all of the digits
from the balance reading on your report sheet. Do not round off or drop any zeros!
Mass of beaker:
__________g
Mass of stopper:
__________g
Mass of disc#
:
__________g
b. Pour just enough rock salt into the beaker you weighed in the previous step to cover the
bottom of the beaker. Then, estimate the mass and write down your estimation.
Estimated mass of salt:
__________g
Use the balance to determine the mass of your salt, and record the value.
Mass of salt + beaker:
__________g
Calculations
Mass of salt:
__________g
Instructor’s Initial:_______
c. Set the salt aside (perhaps on the watchglass or a piece of paper towel) for use in part D.
d. Pour about 1 g of sugar into the same beaker. Estimate and measure the mass of the sugar,
just as you did in part b.
Estimated mass of sugar:
__________g
Mass of sugar + beaker:
__________g
Mass of sugar:
__________g
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D. Measuring Temperature
a. Determine the temperature of the room by simply reading the value on your thermometer.
Note that if the temperature reading appears to be “on the line”, you should write .0 at the
end of the measurement; if it is between the lines you should write .5
Temperature of room:
_________oC
b. Fill your 250-mL beaker about half way to the top with deionized (DI) water. Then, record the
temperature of the water.
Temperature of water:
_________oC
c. Put a handful of ice into the beaker, and stir it for about a minute with your glass stirring rod
(never stir with your thermometer!) Then, record the temperature of the slush you have
made.
Temperature of ice-water:
_________oC
d. Pour the salt from Section C into the ice water, and stir it for about two minutes. Record the
temperature of this mixture.
Temperature of ice water:
with salt
_________oC
Copy all values from these sheets over to the Report Sheet. Do not forget to copy all units!
You will only turn in the Report Sheet when you are done. Save the remainder to help
you review for the lab final.
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Report Sheet
Name:________________________
MEASUREMENTS
1. Measuring Length
a. What units are represented by the numbers marked on the meterstick? ________________
There are ____________ centimeters in 1 meter.
There are _____________ millimeters in 1 cm.
There are ____________ millimeters in 1 m.
b.
Estimated value
Measurement
Length of the paper
Width of the paper
c. Length of your shoe __________________
2. Measuring Volume
Estimated volume of the test tube _______________________
Largest cylinder
Medium cylinder
Smallest cylinder
Size of the cylinder
(in mL)
Volume of water
from the test tube
Estimated volume of one gallon of water __________________________
Actual volume of one gallon of water ________________________
C. Measuring Mass
a. mass of 50-mL beaker __________________
b. mass of the stopper ____________________
c. mass of the disk ___________________ code # of the disk __________________
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d.
Estimated value
Measurement
5 g of salt
1 g of sugar
D. Measuring Temperature
a. Temperature of the air in the room________________
b. Temperature of the water_______________
c. Temperature of the ice-water_________________
d. Temperature of the salt/ice-water mixture______________________
Be sure that you have included the correct units for all answers, where appropriate!
Questions
.
1. Balances can be used to weigh objects of many different masses and sizes. Why would a
balance at a truck-stop which is used to weigh 18-wheelers and their cargo be inappropriate for
determining your own weight? Be as specific as possible.
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2. Devise a way to measure the approximate thickness of a single sheet of paper in millimeters,
using a ruler and paper (and maybe a calculator) as your only tools. (Only suggest a procedure;
you do not need to carry it out.) Then, list the steps you would use clearly and in order.
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Materials for this experiment:
Meter sticks
String
Size 4 stoppers
Unknown metal disks
5
one-gallon plastic bottle
salt 5 g/ student
sugar 10 g per student
5 one-liter graduated cylinder
ice
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