CHEMISTRY LAB #1
Stations Lab: Scientific Measurement
Introduction
Every measurement has an uncertainty, or built-in error. This error is due to limitations in the
measurement scale, the manufacturing process, and the ability of the human eye to detect small
differences. For example, when measuring volume with a graduated cylinder, the width of the
scale lines, variations in glass thickness, and slight changes in your angle of sight when reading
the scale are just some of the factors that can cause uncertainty. Because of this uncertainty, no
measurement made in science should be thought of as an exact value, but rather as a value within
a range that varies with the uncertainty.
Purpose
To become familiar with the measurement scale of electronic balances, triple beam balances,
graduated cylinders, and rulers; to make several different kinds of measurements and compare
the uncertainty between them.
Equipment
Triple beam balance
250ml Beaker
2 Paper clips
Irregular Shaped Object
Unknown solid
Scoop
Ruler
Electronic Scales
Graduated Cylinder
2 Pencils
Box
Filter paper or plastic boat
2 Pennies
Procedure
This is a Station Lab. There are five stations and each group will have 5 minutes to complete
each station. At each station, the group will perform a measurement that is commonly used in a
chemistry lab. Once the measurement is completed, each member of the group will record the
results in the appropriate table/chart. Once the allotted time has passed, the group will rotate to
the next station. This process will continue until each group has completed all of the stations.
Station #1
At this station, you will be measuring the mass of both a small and large paperclip (one at a time)
on the triple beam balance and the digital scales. Record the results from each measurement in
the appropriate space in the table. Be sure to use the correct units.
Item
Large Clip
Small Clip
Penny (Pre 1982)
Penny (Post 1982)
Triple Beam Balance
Digital Scale
Difference
Station #2
At this station, you will measure the length and diameter of two pencils and calculate
circumference, surface area, and volume. When the required measurements are completed,
record the results in the appropriate space in the following table. Record all measurements in the
appropriate metric unit.
Item
Pencil 1
(long)
Pencil 2
(short)
Length
Diameter
Circumference
Surface Area
Volume
Station #3
At this station, you will be finding the volume of two irregular shaped objects using
displacement. (For further directions, see the description on the attached handout.) Record your
findings in the appropriate space in the following table using the correct units.
Item
Water Level
Before Object
Water Level
After Object
Volume
Object 1
Marble
Station #4
At this station, you will measure out a specific amount (5.25 grams) of an unknown solid using
both the triple beam balance and digital scale. DO NOT place chemicals directly on the pan of
the scales. To accomplish this station, you will need to use either a plastic boat or filter paper as
a barrier. Record your results in the following table.
Item
Triple Beam
Balance
Digital Scales
Difference
Station #5
Mass of Boat or
Filter
Mass of Substance
Mass of Substance
+ Barrier
At this station, you will measure the dimensions of a box and calculate the volume and surface
area. Record all measurements in the appropriate space in the following table using the correct
metric units.
Length
Width
Height
Surface Area
Volume
Post Lab Questions
1. How different were the measurements made on the three balances? Which balance do you
think would be the best to use in lab activities? Why?
2. The method of determining the volume of an object by submerging it in water is called
“volume displacement”. Identify one advantage and one disadvantage for this method.
Errors
Think of two possible errors you may have committed in this lab that may have somehow affected
your results and record them below. Explain the specific steps you will take to avoid each of
these errors in the future.
1.
2.
Conclusion
Describe what you learned while doing this lab: