P2P
January
13,
2009
Blue
Licks
State
Park
Floating
and
Sinking
1
Activities
I.
Sorting
Learning
Target:
I
can
sort
objects
based
on
whether
they
float
or
sink
in
water.
Need:
Bucket
of
many
objects
Two
pieces
of
aluminum
foil:
about
2
inches
square
each
Pitcher
of
water
Bowl
for
filling
with
water
Paper
towels
For
this
activity,
you
will
use
the
bucket
of
objects
you
had
previously
sorted
into
different
categories.
Place
paper
towels
around
to
sop
up
spilled
water.
Fill
the
bowl
about
half
way
with
water,
and
add
objects
from
the
bucket
one
at
a
time
to
determine
if
they
float
or
not.
You
might
have
to
push
some
objects
under
the
water
briefly
to
get
them
completely
wet
to
see
if
they
really
float
or
not.
Test
about
20‐30
objects.
Record
in
your
notebook
whether
each
object
floats
or
sinks.
Make
a
table
showing
the
following:
Name
of
the
object
(rows)
Whether
the
object
floats
or
not.
(columns;
and
columns
for
the
rest)
What
the
object
is
made
out
of
(use
your
best
guess
if
unsure)
What
is
the
object
is
mostly
used
for
(or
guess
if
unsure)
Do
all
floating
objects
float
equally
well?
In
other
words,
if
they
float,
is
the
same
amount
of
the
object
above
the
water
for
each?
Write
a
rule
that
predicts
what
it
is
about
an
object
that
determines
floating
and
sinking:
share
this
rule
with
each
other
in
the
group,
and
share
with
a
facilitator.
Now
turn
to
the
aluminum
sheets.
Take
one
of
them,
keep
it
flat,
and
see
if
it
sinks
or
floats.
Now
take
the
other
one,
and
fold
it
into
the
shape
of
a
boat
and
see
if
it
sinks
or
floats.
Wad
up
the
other
(still
flat)
sheet
into
a
tiny
aluminum
ball
and
see
if
it
sinks
or
floats.
Is
shape
one
way
to
tell
if
an
object
sinks
or
floats?
2
II.
Balancing/determining
weight
Learning
Targets:
I
can
tell
whether
one
object
weighs
more
than
another
by
balancing
them.
I
can
sort
a
group
of
similar
objects
from
lightest
to
heaviest.
I
can
identify
standard
mass
objects.
I
can
use
standard
mass
objects
to
determine
the
mass
of
an
unknown
object.
[I
can
distinguish
between
mass
and
weight]
Need:
Bucket
of
objects
again
Metal
nuts
(probably
20
or
so
per
group)
Clothespins
(4
per
group)
Standard
plastic
1‐gram/1‐cubic
centimeter
cubes
2‐pan
balances
Electronic
scales
Experiment
with
the
balance,
using
objects
provided
at
your
table.
Record
your
results
in
your
notebook.
Some
ideas
for
exploration
might
include
the
following:
Does
it
make
a
difference
where
the
objects
are
placed
in
the
pans?
Does
it
make
a
difference
if
you
switch
the
objects
and
put
them
in
opposite
pans?
Set
up
your
balance
so
that
it
appears
to
balance,
then
discuss
with
your
group
what
the
term
balance
means
(as
a
verb).
How
should
your
balance
look
before
loads
are
placed
in
the
pans?
Try
to
write
a
definition
for
balance.
Record
your
current
ideas
about
balancing
at
this
point
in
your
notebook.
Later
on,
you
may
choose
to
modify
your
definition.
What
similarity
do
you
observe
among
objects
that
balance
one
another?
What
differences
do
you
observe
among
the
objects
that
do
not
balance
one
another?

Check
your
ideas
with
a
facilitator.
Take
two
objects
and
place
them
on
opposite
sides
of
the
balance.
Do
they
balance?
If
not,
how
can
you
use
the
balance
to
order
or
rank
them?
3
Select
a
third
object
and
use
the
balance
to
come
up
with
a
ranking
for
all
three
objects.
Add
up
to
eight
more
objects
to
the
ranking
you
came
up
with
above.
Obtain
some
metal
nuts.
Take
the
objects
that
you
ranked
in
part
A
and
balance
them
one
at
a
time,
with
the
metal
nuts.
Record
your
results.
Do
any
two
objects
balance
with
the
same
number
of
metal
nuts?
If
so,
what
happens
when
those
objects
are
placed
o
opposite
sides
of
a
balance?
How
can
you
use
square
nuts
to
order
or
rank
objects?
How
does
the
ranking
you
obtain
compare
to
the
ranking
you
obtained
in
part
A
of
this
experiment?
The
number
of
metal
nuts
that
balance
with
an
object
tells
us
something
useful
about
that
object.
If
two
objects
balance
the
same
number
of
nuts,
then
the
two
objects
will
balance
with
each
other.
If
one
object
balances
with
more
nuts,
then
the
two
objects
will
not
balance
with
each
other.
We
will
call
the
number
of
metal
nuts
that
balance
an
object
the
mass
of
the
object.
Take
two
objects
that
do
not
balance.
How
can
you
use
your
balance
and
the
above
experiments
to
determine
how
much
more
mass
one
object
has
than
the
other?
Consider
two
objects
that
balance
a
different
number
of
square
nuts.
Discuss
in
your
group
what
you
can
say
about
the
masses
of
those
objects.
 Check
your
answers
with
a
facilitator.
Imagine
that
another
group
has
decided
to
use
clothespins
for
their
experiments
instead
of
square
nuts.
The
people
in
the
other
group
found
that
a
certain
small
book
balances
six
identical
clothespins.
What
answer
would
those
folks
give
to
the
question:
What
is
the
mass
of
the
book?
Decide
on
a
way
to
use
the
clothespins
you
have
been
given
and
your
square
nuts
to
answer
the
following
question:
What
mass
would
you
measure
for
that
book
if
you
were
to
find
the
mass
of
the
book
in
nuts?
Discuss
your
reasoning
with
your
group.
4
Name
a
set
of
objects
besides
square
nuts
or
clothespins
that
you
could
use
to
measure
the
mass
of
the
book.
What
property
must
those
objects
have
in
order
to
be
able
to
use
them
to
measure
mass?
Discuss
with
your
group
and
write
your
response
in
your
notebook.
Also
write
responses
to
each
of
the
following
problems:
Using
metal
nuts,
what
mass
would
you
measure
for
each
of
the
following
objects?
1.
2.
3.
4.
An
egg
that
balances
4
clothespins.
A
plant
that
balances
15
clothespins.
A
plant
that
has
a
mass
of
15
clothespins.
A
glass
of
water
with
a
mass
of
30
clothespins.
What
mass
would
the
students
in
the
other
class
measure
for
each
of
the
following
objects?
1. A
mouse
that
balances
10
metal
nuts.
2. A
cup
that
balances
4
nuts.
3. A
shoe
that
has
a
mass
of
100
nuts.
 Explain
your
reasoning
to
a
facilitator.
Two
students
are
discussing
their
homework
from
the
night
before.
They
had
been
told
to
go
home
and
find
the
mass
of
a
pet
with
the
wood
blocks
(instead
of
nuts
or
clothespins)
they
had
been
using
in
class
to
measure
mass.
The
first
student
found
that
her
pet
had
a
mass
of
50
blocks
and
the
other
student
found
that
his
pet
had
a
mass
of
65
blocks.
What
information
do
you
have
about
each
student’s
pet?
Is
it
possible
that
one
of
the
pets
is
a
gerbil?
A
German
shepherd?
Discuss
your
reasoning
in
your
groups
and
write
it
down.
Would
you
know
more
if
you
knew
they
were
using
metal
nuts
to
measure
the
masses
of
their
pets?
In
the
preceding
exercise,
you
saw
that
if
other
people
used
the
same
set
of
objects
as
you
did
to
measure
mass,
then
you
knew
more
about
their
measurements
than
if
they
used
a
different
set
of
objects.
In
the
next
activity,
you
will
use
a
set
of
standard
objects
that
are
available
to
many
people.
When
mass
is
measured
using
this
mass
standard,
the
mass
is
said
to
be
measured
in
grams.
In
the
following
experiments,
you
will
explore
grams
as
a
measure
of
mass.
5
Each
of
the
plastic
cubes
has
a
mass
of
1
gram.
Using
these
cubes
and
your
balances,
determine
the
mass
of
each
metal
nut,
and
the
mass
of
each
clothespin.
Is
it
possible
to
convert
the
mass
of
any
object,
measured
in
gram
units,
into
nut
units
or
into
clothespin
units?
How?
Measure
the
mass
of
another
of
the
bucket
objects
using
metal
nuts.
Predict
the
number
of
gram
pieces
you
would
have
to
use
to
balance
the
object.
Explain
how
you
arrived
at
your
answer.
Then
check
your
prediction.
Now
measure
the
mass
of
a
different
object
using
your
standard
mass
set.
How
many
nuts
would
it
take
to
balance
that
object?
Check
your
prediction.
 Explain
your
reasoning
to
a
facilitator.
In
this
activity,
you
saw
that
any
measurement
of
mass
using
the
nuts
can
be
converted
to
a
measurement
using
gram
masses.
Likewise,
any
measurement
of
mass
in
grams
can
be
converted
to
a
measurement
of
mass
in
nuts.
Rather
than
continue
to
use
the
nuts,
which
are
unique
to
this
workshop,
we
will
use
the
standard
masses.
Determine
how
many
standard
gram
masses
are
required
to
balance
one
clothespin.
Can
you
tell
if
the
balancing
is
exact?
Is
it
possible
to
tell
with
this
set‐up
exactly
how
many
grams
the
clothespin
weighs?
Why?
[X‐rated:
For
middle
school
discussion,
but
teachers
of
all
ages
need
to
know
this.]
Balancing
with
standard
masses
determines
the
mass
of
an
object,
but
the
instrument
is
limited
in
precision.
A
more
precise
weighing
device
is
an
electronic
scale.
This
has
a
single
pan,
and
instead
of
balancing
the
masses
of
two
objects,
it
compares
the
weight
due
to
the
gravitational
attraction
of
the
earth
with
the
force
due
to
internal
springs.
It
can
be
adjusted
so
that
the
output
measures
in
gram
units,
but
it
is
not
determining
mass,
it
is
instead
measuring
weight.
Mass
is
measured
with
a
balance,
while
weight
may
be
measured
with
a
scale.
If
you
were
to
measure
your
weight
with
a
scale
on
earth,
then
on
the
moon,
the
numbers
will
be
different
because
the
force
due
to
the
spring
stays
the
same,
but
the
force
due
to
gravity
changes.
A
balance
gives
the
same
answer
in
both
places,
because
you
are
comparing
the
same
type
of
thing
–
a
standard
mass
with
an
unknown
mass.
Using
the
electronic
scales
provided,
measure
the
mass
of
each
of
the
following:
the
metal
nut,
a
clothespin,
and
the
1‐gram
standard
cube.
Is
the
math
you
used
to
6
determine
the
mass
of
these
objects
consistent
with
the
masses
of
each
determined
with
the
scale?
7
III.
Dividing
and
calculating
density
Learning
Targets:
I
can
choose
appropriate
mathematical
operations
to
solve
given
problems.
I
can
set
up
division
problems
to
give
the
correct
answer
to
a
problem.
I
can
use
measured
values
of
solids
or
liquids
to
determine
their
density.
I
can
sort
properties
of
objects
based
on
whether
the
properties
are
characteristic
or
not.
Need:
100‐mL
graduated
cylinders
Standard
plastic
cubes
Wooden
dowels
and
iron
bars
Mass
and
volume
both
tell
how
much
of
something
there
is.
We
could
either
say
“we
have
10
cm3
of
aluminum,”
or
we
could
say,
“we
have
27
g
of
aluminum.”
Both
of
these
statements
tell
how
much
aluminum
we
have.
But
mass
and
volume
are
not
the
same.
Their
definitions
are
completely
different.
The
definition
of
mass
involves
the
use
of
a
balance
to
compare
the
measured
object
with
standard
objects.
The
definition
of
volume
involves
fitting
cubes
inside
the
object
being
measured.
The
mass
of
an
object
tells
us
how
heavy
it
is;
the
volume
of
an
object
tells
us
how
much
space
it
takes
up.
What
has
happened
here
is
that
one
concept,
amount,
as
been
replaced
with
two
different,
precisely
defined
concepts:
mass
and
volume.
The
concept
of
an
amount
of
material
is
too
vague
to
be
used
in
science.
We
must
always
specify
whether
we
are
talking
about
the
mass
of
the
material
or
the
volume
of
the
material,
or
perhaps
some
other
sense
of
amount.
The
statement
“we
have
the
same
amount
of
water
and
mercury”
is
meaningless.
We
might
have
the
same
volume
of
water
and
mercury,
but
then
the
mercury
would
be
heavier.
We
might
have
the
same
mass
of
water
and
mercury,
but
then
the
water
would
fill
a
larger
container
than
the
mercury.
Consider
an
experiment,
shown
below,
in
which
we
dissolve
an
Alka‐Seltzer
tablet
in
water.
Suppose
that
immediately
after
the
tablet
is
placed
in
a
bottle,
a
tight‐fitting
balloon
is
fitted
over
the
mouth
of
the
bottle.
The
tablet
then
dissolves
and
the
balloon
becomes
inflated
as
shown
in
the
diagram.
Consider
the
system
consisting
of
everything
inside
the
bottle
and
balloon.
Discuss
the
following
with
your
group.
8
A. When
the
tablet
dissolves,
does
the
volume
of
the
system
increase,
decrease,
or
remain
the
same?
B. When
the
tablet
dissolves,
does
the
mass
of
the
system
increase,
decrease,
or
remain
the
same?
For
this
activity,
you
will
need
the
graduated
cylinder,
water,
and
the
standard
cubes.
Determine
the
volume
(by
displacement)
and
mass
(using
the
scale)
of
the
following:
1
cube,
2
cubes,
3
cubes,
4
cubes,
7
cubes,
and
10
cubes.
For
each
situation,
determine
the
number
you
get
when
you
divide
the
mass
by
the
volume.
Set
up
a
table
with
4
columns:
one
column
for
number
of
objects,
one
for
their
mass,
one
for
their
volume,
and
the
final
one
for
the
result
of
the
division.
What
do
you
see
in
the
division
column?
What
does
this
tell
you
about
these
objects?
If
you
had
50
cubes,
what
would
this
number
be?
If
you
had
5000
cubes,
what
would
it
be?
How
are
you
certain
of
this?
If
you
had
a
very
large
object
made
of
exactly
the
same
material
as
these
plastic
cubes,
what
would
the
answer
of
the
division
of
its
mass
by
its
volume
be?
In
a
more
general
sense,
do
you
suppose
there
is
a
consistent
idea
here?
Discuss
with
your
group,
then
write
down
a
rule
to
predict
whether
the
number
you
obtain
by
dividing
the
mass
by
the
volume
for
any
sample
of
an
object
will
be
the
same
as
any
other
sample.
Suppose
you
do
this
activity
with
a
chocolate
chip
cookie,
instead
of
with
a
sample
of
plastic.
Is
the
result
of
the
above
calculation
the
same
for
every
piece
of
the
chocolate
chip
cookie,
in
the
same
way
you
determined
for
the
plastic
cubes?
Why?
If
an
object
or
sample
of
liquid
is
the
same
throughout,
it
is
said
to
be
homogeneous.
A
piece
of
plastic
is
homogeneous
because
all
parts
of
it
are
the
same
material.
The
way
to
test
the
homogeneity
of
something
is
to
compare
tiny
pieces
of
it
taken
from
different
parts.
If
this
is
done
to
a
chocolate
chip
cookie,
some
of
the
tiny
pieces
will
be
chocolate
and
some
will
be
cookie.
A
chocolate
chip
cookie
is
therefore
said
to
be
inhomogeneous
because
not
all
parts
of
it
are
made
of
the
same
material.
Glass,
pure
water,
and
copper
are
homogeneous;
tiny
pieces
taken
from
them
are
always
the
same
material.
Bread
has
air
pockets,
and
dirt
contains
many
things,
so
both
of
these
are
inhomogeneous.
For
homogeneous
materials,
mass
divided
by
volume
always
gives
the
same
number
of
the
same
substance.
This
relation
between
mass
and
volume
is
called
a
proportion.
It
is
said
that
the
mass
and
volume
of
the
substance
are
proportional
to
each
other.
When
two
properties
such
as
mass
and
volume
are
divided
by
each
other,
the
result
is
called
the
ratio
between
them.
When
the
ratios
are
equal
for
any
sample,
these
properties
are
proportional.
9
In
the
preceding
section,
you
worked
several
problems
using
the
ratio
of
mass
to
volume.
You
found
that
mass
and
volume
are
proportional
for
a
given
homogeneous
substance.
Therefore,
the
ratio
of
mass
to
volume
is
the
same
for
all
samples
of
the
substance.
Density
is
the
name
given
to
this
ratio.
Mass,
volume,
and
density
are
all
properties
of
matter.
However,
mass
and
volume
tell
us
something
about
a
specific
object.
In
contrast,
the
density
contains
information
about
a
class
of
objects:
under
the
same
conditions,
all
objects
made
of
the
same
material
have
the
same
density.
(This
is
not
true
for
mass
and
volume.)
We
use
the
term
characteristic
property
to
refer
to
properties
such
as
density
that
characterize
a
particular
material
or
substance.
Characteristic
properties
can
be
used
to
help
identify
the
material
out
of
which
a
given
object
is
made.
Obtain
2
solid
objects
from
the
facilitators:
a
wooden
dowel
and
an
iron
bar.
The
purpose
of
this
experiment
is
to
measure
the
density
of
these
objects
by
following
the
procedure
of
density
determination:
measure
the
mass,
measure
the
volume,
and
divide
mass
by
volume.
A.
Measure
the
mass
of
one
of
the
objects
as
accurately
as
possible
and
write
it
down.
Determine
the
volume
of
the
object
using
the
displacement
of
water
in
a
graduated
cylinder,
and
write
this
volume
down.
Using
this
data,
calculate
its
density
and
record
it
in
your
notebooks.
Repeat
for
the
other
object.
B.
Measure
the
density
of
water.
Make
the
most
accurate
measurement
of
the
mass
and
volume
possible.
Discuss
with
your
group
how
best
to
make
these
measurements.
Give
your
calculated
value
for
the
density.
Is
the
density
of
water
greater
or
less
than
the
density
of
each
object?
Does
each
object
float
or
sink
in
water?
Write
a
rule
to
predict,
from
mass
and
volume
data,
whether
an
object
will
sink
or
float
in
water.
 Check
your
results
with
your
instructor.
10