Laboratory Procedures
A. Determining Measurements and Data Collection
1. Measuring length: Use the meterstick to
measure the length of the following items in centimeters (cm) using
significant figures. Measure to the nearest 0.1 cm for all length
masurements.
Your little fingernail _________ cm
The distance around your wrist _________ cm
The length of your shoe _________ cm
Your height _________ cm
2. Determine and record the length and width of the sides of the rectangle drawn on the board. Calculate the area of the rectangle using the formula: Area = L x W.
Compare your results to those of two other classmates.
Measurements Length (cm) Width (cm) Area (cm2)
Person 1 ________ _________ __________
Person 2 ________ _________ __________
Person
3
________
_________ __________
B. Comparing Metric and American Units of Length
1. Using a ruler and a meterstick, determine the number of centimeters (to 0.1 cm) that correspond to a distance of 12.0 inches.
12.0 inches = ______ cm
Divide the number of centimeters that you measured by 12.0 inches. Be sure to show your calculations. The result is your experimental value for the number of centimeters in 1.0 inch.
Calculations:
Experimental conversion factor: __________cm/in
C. Measuring Volume of Solid
1. Volume of Solid Direct Measurement Obtain
an unknown
solid sample from your instructor.
a) Record the unknown # ___________
b) Record its shape. __________
c) Use the meterstick to determine the dimensions of the solid in centimeters. (Since the equation for determining volume depends on the shape of the object, use the chart below to determine which dimensions are needed to determine the volume of your solid object. For example, if the object is a cube, only length is needed.)
length (L):________, width (W) :________, height (H) :________, diameter (D):_______
d) Use the table below to calculate the volume of the solid.
Shape Dimensions Volume (cm3)
cube length (L) V = L3
rectangular length (L), width (W), height (H) V = L x W x H
cylinder diameter (D), height (H) V = (3.14 x D2 x H)/4
Show formula and calculations:
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Calculated volume found by direct measurement: _____________.
2. Volume of a Solid by Volume Displacement When a solid object is submerged under water, it displaces the water by the amount of its own volume. The difference in the water level before and after the object is submerged is equal to the volume of the object submerged.
a) Obtain a 25-mL graduated cylinder and fill it with water until
it is
about half full. Record the volume of the water. Tie a piece of thread
around
your solid sample used in part C1 above, and slowly submerge it
into
the graduated cylinder being careful not to splash any drops of water
on
the sides of the cylinder. Record the new volume of the water to the
nearest 0.1 mL.
Volume of water before object submerged: ________ mL
Volume of water after object submerged: ________ mL
Calculate the volume displaced by the object:
Vol after submerged - vol before submerged = vol displaced = vol of the
solid
in mL
b) Convert the volume of the solid from milliliters to cubic
centimeters (1 mL = 1 cm3)
Calculated volume found by volume displacement: ___________ cm3
D. Determining the Mass of Solid
1. Demonstration: Your lab instructor will demonstrate the proper use of the laboratory balance.
Notes:
2. Mass of Solid: Determine the mass of your
solid object using the balance (to the nearest 0.001g).
Mass of Solid: _________
E. Determining the Density of Solid
Density is defined as mass in grams per unit volume in milliliters or g/mL.
Density of solid = Mass (g) of solid/Volume (mL) of solid
1. Calculating the density of the solid: Using the mass of the solid that you determined in part D and the volume of the solid that you determined in part C (by displacement), calculate the density of your solid object.
Show your calculations:
Density of solid object: ______________
Questions to be addressed in your conclusion:
F What are some reasons that the resulting values for the area of the rectangle determined in part A might vary from person to person?
F In part B, how does your experimental conversion factor for cm to inches compare to the theoretical value of 2.54 cm/in?
F In part C, how close are the
results
for the volume of the solid from measuring the dimensions to the volume
you
determined
by displacement of water?
F Which method of volume measurement
do you
think is most accurate: direct measurement or measurement by
displacement ? Why?
F After having determined the density
of
a solid, briefly describe how you would propose to experimentally
determine the
density of a liquid.
(updated 1-4-07 P Powers)