Density and Flotation
• Task: Given 3 eggs,
salt, water, and 3
beakers, make it so
that one egg sinks,
one egg floats and
one egg stays
suspended in the
middle of the
water.
• Objects sink or float
based upon density.
• If an object is less dense
that water (p < 1g/cm3)
it will float.
• If an object is more
dense than water (p <
1g/cm3) it will sink.
Object
Density (g/cm3)
Aluminum
2.7 g/cm3
Penny
7.2 g/cm3
Gold
19.3 g/cm3
Wood
0.85g/cm3
Sugar
1.6g/cm3
Ice
0.917g/cm3
Baby Oil
0.83g/cm3
Mercury
13.94g/cm3
Sink or Float
Will a penny sink or float in liquid mercury?
Mercury Video
QUIZ: make an 8 item density column.
7 Layer Density Column
Object
Density g/cm3
Honey
1.42
Light Corn Syrup
1.33
Dawn Dish Soap
1.06
Water
1.00
Vegetable Oil
.92
Baby Oil
.83
Rubbing Alcohol
0.79
You must use 3 solids!
Hand in a labeled picture in COLOR! Bring it in for extra credit!
Objects generally sink or float based upon density.
• More dense = sinks
• Less dense - floats
How much of an Object
will Float above Water?
0.92g/cm3
robject
*100 = % Submerged
rwater
7.13g/cm3
The zinc will sink as its denser than water
ICE
CUBE
Zinc
The ice floats as its less dense than water
But how much is underneath the water?
About 8%
visible
0.92 g cm3
*100
=
92%
submerged
g
1 cm3
If 92% is under water then
the other 8% is visible!
Just the Tip of the Iceberg!!!
Photo via: Adventure-Journal
90% of this ice berg is below water (salt water)
Artistic Rendition
of an iceberg.
Most of an Iceberg is
below water!
Think about this and
ships traveling in the
ocean.
Wiki commons
The TITANIC
Flotation Problems (Handout)
Knock on Wood
• A branch snaps and falls
into a river. It has a density
of 0.7g/cm3, will it sink or
float and if it floats how
much of it will be visible?
Floating Basketball
• A basketball has a mass of
624g and a volume of
7512cm3. What percentage
of a basketball will be visible
above water?
robject
*100 = % Submerged
rwater
Rank each object from the most
dense to the least dense:
B
A
D
C
F
E
Most Dense
[1]
[2]
[3]
[4]
[5]
[6]
Least Dense