6th period
MAKING SENSE OF DENSITY
Purpose
Is density a characteristic property of a substance?
Research
In your notebook, write out definitions for characteristic property AND density
Hypothesis
If you break an object in half, does its density change? What do you think? Write your answer as
your hypothesis
Experiment
Materials:
*triple-beam balance *100 mL graduated cylinder
*beaker of water
*paper towels *crayon, without paper
*2 marbles (same style/size)*ball of clay, approximately 5 cm wide
Procedure:
1. Use a balance to find the mass of the clay. Record the mass in your data table.
2. Add enough water to the graduated cylinder so that the clay can be completely submerged. Measure
the initial volume of the water BEFORE you put the clay in it. Record this on your volume calculations
page as the initial volume.
3. Roll the clay into a stick shape and place the clay in the graduated cylinder. Measure the new volume
of the water. Record on your volume calculation page (clay + water).
4. Calculate the difference of the two measurements, showing your work on the volume calculation
page. This difference is the volume of the clay. Record on your data table.
5. The density of the clay equals its mass divided by its volume. Fill out the calculations page for
density and record your final answer on your data table.
6. Thoroughly dry the clay with a paper towel. Carefully separate the clay into 2 pieces, being sure to
not lose any of the clay in the process. Repeat steps 1 through 5 to calculate and record the densities of
each of the two pieces.
7. Repeat steps 1 through 6 using the crayon (remember to take the wrapper off).
8. Repeat steps 1 through 6 using the 2 marbles (treat the two marbles as one marble and then be sure
to calculate the volume of each individual marble).
Analysis
You’ll be given a copy of all of the data tables. You need to fill them
out as you go.
Conclusion
***Remember to write this AFTER the data tables
Write a paragraph that answers:
- For each of the three objects you tested, how does the density
of the whole object compare with the densities of EACH of the
pieces? Is it close?
- Is density a useful property to help you identify a substance?
Explain. (In other words, if I gave you a piece of “mystery object
#1”, would you be able to tell if it was made of crayon, clay, or
marbles by figuring out its density?)
- Why did you have to dry the objects off in step #6?
- What would you do differently if you were to start this
experiment over?
Data Table:
Object
Volume (cm3)
Mass (g)
Clay
Density (g/cm3)
Whole
Piece 1
Piece 2
Crayon
Whole
Piece 1
Piece 2
Marbles
Both
Piece 1
Piece 2
Volume Calculations Section: Record these answers in the Volume column of your data table
Clay:
Whole--
_________ Clay + water #1--
_________
- _________ initial water
#2_________
- _________
_________
Crayon:
Whole--
_________ Crayon + water
#1--
- _________ initial water
_________ #2-- _________
- _________
- _________
Marbles:
Both--
_________ Marbles + water
- _________ initial water
#1--
_________
#2--
- _________
_________
- _________
Density Calculations: Show work by filling in the blanks even when using a calculator!
Remember to record your answers on the data table. Round your answers to the nearest tenth.
Formula for Density: D = mass divided by volume or m/v
Clay:
Whole:
m
_______
D = ________ g/cm3
V
#1:
m
V
_______
D = ________ g/cm3
#2:
m
V
_______
D = ________ g/cm3
Whole:
m
V
_______
D = ________ g/cm3
#1:
m
V
_______
D = ________ g/cm3
#2:
m
V
_______
D = ________ g/cm3
Whole:
m
V
_______
D = ________ g/cm3
#1:
m
V
_______
D = ________ g/cm3
#2:
m
_______
D = ________ g/cm3
Crayon:
Marbles: