Name: _______________________________________________________
Period: ________
Density of an Unknown Solid Lab
Stamps
Stamp for Identity
of Unknown
Stamp for Graph
Introduction –
An old riddle asks “Which has more mass, a kilogram of feathers or a kilogram of gold?” You
(hopefully) know that a kilogram of feathers and a kilogram of gold both have the same mass, one
kilogram. However, you also know that there is something very different about a small gold brick and
a large bag of feathers, even though they have the same mass. The key to answering the riddle is to
understand the relationship and object’s mass and the volume it occupies. This relationship is
expressed by the physical property called density defined as the ratio of a substance’s mass to the
volume it occupies.
Volumes of irregularly shaped solids can be determined by using a displacement. First, place
water in a graduated cylinder and measure the volume. Next, place the solid object into the water and
record the new volume. Subtract the initial volume from the final volume to determine the volume of
the solid.
Purpose: To determine the density of an unknown solid.
Materials:
Balance
Graduated Cylinders
Tap Water
Unknown Solid
Procedure:
□1. Put on your lab apron and safety goggles.
□2. Determine the mass of a sample of your unknown solid. Record mass in data table.
□3. Determine the volume of the solid using the displacement method. (Be sure to use an appropriately
sized graduated cylinder) Record all volume measurements in the Data Table.
□4. Repeat Steps 2 and 3 until you have AT LEAST 3 trials worth of data. Vary the size of your
samples between trials.
□5. Calculate density and average density for your trials. SHOW ALL Work in Calculations section
□6. Compare your experimental density to the values on the chart and calculate the Percent Error for
your experimental density compared to the accepted value.
□7. If your measurements have more than 5% error, you must repeat the experiment until your error
value is below this value (using at least three calculations).
□8. When you have calculated your average density show your teacher and they will check your value
and calculations.
□9. Get a STAMP for your density measurements and calculations with a Percent Error of less than
5%.
□10. Return all equipment and materials to where they belong (if not your bin) and clean your lab
station.
□11. Wash your hands.
Data:
Identity of Unknown Solid: _______________________
Data Table: Determining the Density of an Solid
Trial 1
Trial 2
Mass of Solid (g)
Initial volume of
water (mL)
Volume of water
+ solid (mL)
Volume of solid
(mL)
Density of solid
(g/mL)
Average density
(g/mL)
Identity of
Unknown
Accepted Density
Percent Error
Calculations: SHOW ALL WORK!
1. Calculate the volume of your solid for each of the trials.
2. Calculate the density of your solid for each of the trials.
3. Calculate the average density of your solid.
4. Calculate the percent error for your solid.
Percent error = |Accepted Value – Measured Value| x 100
Accepted Value
Trial 3
Trial 4
Graph:
 Make a graph of plotting your data. Be sure to label your axes and to give your graph a title!
 Graph ONLY your three best data points.
 Draw a straight line of best fit.
 Calculate the slope of the best fit line. Do not use your data points to calculate the slope. Show
your work!