Density Lab: Using Water Displacement
(be sure to read the bottom of the meniscus!!!)
Materials:
Triple beam balance
Graduated cylinder
Several different objects (metal, glass and wood cylinders)
2 Unknowns
Procedure:
1.
2.
3.
4.
5.
6.
7.
Measure the mass of each object with the balance and record this in the
“mass” column.
Pour some water in the graduated cylinder (the initial amount is not
important, but be sure to record it under “initial water volume”.
Carefully add one of the objects without splashing any of the water out of
the graduated cylinder and record the new displaced volume.
Subtract the difference between the initial and displaced volumes and this
is the actual volume of the object. Record this under “actual volume” of
object.
Repeat steps 3-4 for each of the objects.
When finished put the objects back in their container, clean and dry your
area, and ask to be checked out of lab.
Go back to your table and calculate the density of the objects using the
density equation: Density = Mass / Volume
IF THE OBJECT CANNOT BE PLACED INTO THE GRADUATED
CYLINDER, FIND THE MASS USING MASS/ VOLUME METHOD.
1
DATA TABLE #1
Name of object
Mass of
object
(grams)
Initial
Water
Volume
(mL)
Displaced
Volume (mL)
Actual Volume of
object
(Displaced – Initial)
OR
LxWxH
Density
g/ mL
or g/ m3
Aluminum
Copper
Zinc
Pine
Oak
Iron
Cork
UNKNOWN #1
Description:
_________________
UNKNOWN #2
Description:
_________________
UNKNOWN #3
Description:
_________________
1.
Using the DATA of the KNOWN DENSITIES, Compare those to the data you collected. Show the
percent error of your data for at least 3 solids. SHOW ALL WORK FOR CREDIT
Formula to use:
Reference data – experimental data / reference data X 100 = ________________
(from the periodic table ) - (from your density calculation) / (from the periodic table ) X 100
Object # 1 __________________
Calculations:
2
Object # 2 __________________
Calculations:
Object # 3 __________________
Calculations:
UNKNOWN OBJECTS: BASED ON THE DENSITY, WHAT DO YOU THINK THE UNKNOWN OBJECTS
ARE? (USE THE PERIODIC TABLE OF DENSITIES AND THE BOOK P11)
#1________________________
#2________________________ #3_______________
CONCLUSIONS: Use complete sentences for full credit
1. WHY DO YOU THINK THE DENSITIES YOU CALCULATED WERE DIFFERENT THAN THOSE IN THE
BOOK OR THE CHART?
2. What effect does mass have on density?
3. What is displacement?
4. Which method seems easier to use: displacement or measurement? Why?
5. How confident are you that your UNKNOWN objects were correctly identified? Please
explain your answer.
6. If the density of water is 1g/ml, which of the objects would you expect to float? Explain your
answer.
3
4