Cube Activity pg. 69
Question: Do cubes of exactly the
same size and shape have the same
mass?
Analysis Questions
 1) Give an explanation as WHY one feels heavier. (what
causes an object to have a different mass from another)
 2)
Description
of cube –
color, size,
shape
Picture of
arrangement
of the
molecules
Mass
(g)
Volume
(cm3)
1)Gold cube
136
15.62
2) Silver
cube
45
15.62
Correct Arrangement
 Heavy substance-smaller and more compacted
molecules
 Lighter substance-larger and less
Compacted molecules
Density Lab pg 70
Problem: How are the volume and
mass of a substance related?
Hypothesis: If the molecules of one
object are smaller and more compact
than another, then its density will be
greater because there are more
molecules in each volume of the
denser object.
Materials
Two sets of metals of different
shapes
Graduated Cylinder
Metric Ruler
Water
Mass balance
Procedures
1. Weigh each shape on a mass balance
BEFORE measuring the volume
2. Record each shape’s mass in the data table
3. Measure the cubes’ volume using the
metric
ruler (V=l*w*h)
4. Measure the volume of the other two
shapes with the graduated cylinder.
5. Record the volumes in the data table.
6. Graph the data. Create a Volume vs. Mass
graph.
7. Make a best fit line for each metal.
8. Find the slope of BOTH lines.
Metal Color
Shape
Cube
Bar
Cylinder
Cube
Bar
Cylinder
Mass (g)
Volume
(mL)
Conclusion-Big Idea from metals
Lab pg71.
 Objects with the same volume but different masses have
Different-DENSITIES
 DENSITY:
The relationship between the mass of the
substance and how much space it takes up.
 OR how compact the molecules are in a certain
amount of space
 Analogy-House Party
 WHY DO OBJECTS HAVE DIFFERENT DENSITIES?
 The mass of atoms, their size, and how they
are arranged determine the density of a
substance.
 What two measurements do you need to find
to solve for density= MASS and VOLUME
 Formula for Density= Mass/Volume
 Units= g/cm3 or g/mL
 How do you find density from your graph?
SLOPE
 3 equations=
 Densities of known substances: Gold 19.3g/cm3
, Steel 7.6g/cm3 Cooking Oil 0.92g/mL
Density Questions-whiteboard
and Pg. 36
 1) Why do objects have different densities?
 2) How might the factors listed in question #1 cause a
substance to have a higher density? HINT: Use your
answer to #1 to help
 3) How might the factors listed in question #1 cause a
substance to have a lower density? HINT: Use your
answer to #1 to help
 4) Draw the arrangement of the molecules for Copper
that has a density of 8.9g/cm3
 5) Draw the arrangement of the molecules for Aluminum
that has a density of 2.7g/cm3
Pretest pg.31
 The following rods have the SAME MASS but different
VOLUMES
 Predict the densities of each sample by writing- Least
dense, Medium dense, Most dense
 Explain why you think each rod is either the most,
medium, or least dense
Unknown Activity pg. 38
 Question: Do substances with the same mass but
different volumes have the same density?
Description of Mass
 1) the cube-color (g)
and shape
Volume
(cm3 )
Calculated
Density
g/cm3
1)
2)
 2) Use your calculated density to answer: Do objects with
the same mass and different volumes HAVE different
DENSIITIES?
 3) Draw a picture of the arrangement of the particles for
each cube.
 4) what can you conclude about the density with objects
with the same mass but different volumes?
 Pick one a) their densities will be the same,
 b) the one with the larger volume will have the lower density,
 c) the one with the larger volume will have the higher density,
 d) the one with the larger density will be twice as dense.
Pg.29 Identifying Unknown
Metals Lab
 Properties of a substance- how an object looks, feels,
act, what it is used for.
 Examples- color, texture, smell, mass, volume, density,
size, shape, melting point, boiling point
 Brainstorm: We have a bucket of metals. What
property(s) can we use to help identify them?
 Problem: What is the identification of each metal?
 Hypothesis: If we find the mass and the volume of each
metal, then we can identify them because each metal has a
specific relationship which is ___________________.
 We will find the relationship between mass and volume
by using our graph to find the ______________.
 Data
 Data Table #1
Color/Description of
Metal
Volume (cm3)
Mass (g)
Volume (cm3)
Mass
 Data Table #2
Color/Description of
Metal
 Data Table #3
Color/Description of
Metal
Volume (cm3)
Mass
Graph
 Create one graph with three lines!
 Graph each data table separately and then create a
best fit line.
 Use different colors.
Data Evaluation
 DATA EVALUATION
 You will have three data evaluations for each
LINE! Do all four steps for each line.
 Please also write your slope on the line on the
graph.
Results
IDENTIFICATIONS
Use the information on the board to identify your metal
Metal
Real Name
Periodic table
 Look at the periodic table.
 Which atoms do you think have the greatest density?
 Actually the smaller more compacted atoms are more
dense.
 Density explains why certain atoms make up certain
substances. For example
 Plastic is made from carbon and hydrogen. These atoms are very
light.
 Based on what you know about the size, mass, and
arrangement of atoms, explain why a sample of sulfur is
more dense than a sample of calcium.
Answer
 Even though a sulfur atom has less mass than a calcium
atom, many more sulfur atoms can pack together in a
certain amount of space.
 This gives sulfur more mass per volume than calcium,
making it more dense.
Analysis questions continue
 1) The size, mass, and arrangement of atoms affect the
density of a substance.
 If a substance has a high density, what can you guess
about the size, mass, and arrangement of the atoms
that make up the substance?
 2) If a substance has a low density, what can you guess
about the size, mass, and arrangement of the atoms
that make up the substance?