DENSITY DEMOS:

["Misconception Alert," GSLG p. 26, #2.]
Marble versus bowling ball immersed in "Dunk Tank of Science." For 
details, see: extras/Marbles-vs-Bowling-Balls.txt
See also, "Will It Float?" (below).

["Density Dilemnas," GSLG p. 27, #3.]
>> "Rainbow" Column of Liquids: three liquids with different densities,
e.g., corn syrup, water, and alcohol. [See "planning notes" for details 
re: process of setting up the graduated cylinder.]

["Density Dilemnas," GSLG p. 27, #4.]
>> Demo: Fill an aquarium with CO2 gas. Add pieces of dry ice to warm 
water in a beaker in order to create a cloud; "pour" the cloud into the 
aquarium and notice how it floats like a stratus cloud layer above the CO2 
at the bottom of the aquarium. [Note: The preceding demo works and looks 
cool, but it funkifies the tank with excess moisture that is slow to 
dissipate. Bottom line: Skip this demo in favor of the following demo....]
>> Floating ["Party"] Bubbles on "bed" of CO2 in aquarium, produced by ... 

OPTION A
... either of the following reactions:

Alka Seltzer + water --> CO2
or the netralization reaction (acid + base) ...
vinegar + sodium bicarbonate (baking soda) --> water + salt + CO2
C2H4O2 + NaHCO3 --> HOH + ?salt? + CO2

Background Notes:
"Household Vinegar is about 3% acetic acid and 97% water (with a mixture
of a small amount of a few other chemicals). Acetic acid has the formula
C2H4O2. So acetic acid has the elements Carbon (C), Hydrogen (H), and
Oxygen (0).

Baking Soda is called Sodium Hydrogen Carbonate or Sodium BiCarbonate. The
formula is NaHCO3 giving it Sodium (Na, latin for Natrium), Hydrogen (H),
Carbon (C), and Oxygen (O)." [UIUC]

OPTION B (better)
... "dry ice" (solid CO2)
www.airgas.com
www.penguinbrand.com [including a list of local retail vendors]

["Density Dilemnas," GSLG p. 28, #8.]
>> Helium-filled balloon (from either WAT or Science Olympiad)

>> Bubbles Flambe' - Burning bubbles filled with natural gas (methane).
Begin by demo'ing behavior of CO2-filled bubbles (exhaled breath is mostly
CO2); what must be true of gas-filled bubbles that rise in air?
Recipe for "super bubble goo":
http://www.exploratorium.edu/snacks/bubble_tray.html

>> Will It Float?

Given the "Grade 8 Mathematics Formula Sheet" (Math 8 SOLs)(1), Honors G/T 
students make at least one prediction based upon determination of the 
approximate density of a "space figure"(2), e.g., either a marble or 
bowling ball (spheres), (a wooden block (cube), billiard ball (sphere), 
hockey puck (cylinder), etc., by measuring its mass and calculating volume 
(using mensuration formulae) and, in turn, density. See also, SMS 
Agenda/Planner, p. 116 (Mathematics/Solids).

(1)Grade 8 Mathematics Formula Sheet (requires Acrobat Reader >/= 6.0):
http://www.pearsonaccess.com/va/training-center.htm
http://etest.ncs.com/Customers/Virginia/pat_home.htm <-- broken link

(2)Space figures (in contrast with "plane figures") and basic solids:
http://www.mathleague.com/help/geometry/3space.htm

See also: extras/How-to-use-Calipers.txt

==
DEMO-P.O.D.s

>> iceberg image
http://www.wsanford.com/~wsanford/gr8ps/01_green/03_how_tightly_packed/
extras/density_iceberg.jpg
[Note: Follow-up on marble vs. bowling ball demo.]

>> "Rainbow" Column of Liquids: three liquids with different densities, 
e.g., corn syrup, water, and alcohol.

>> Coke Classic vs. Diet Coke immersed in aquarium filled with ...
Day 1: water.
Day 2: saltwater (highly-concentrated solution).
[Note: Follow-on idea: Corn syrup is the ingredient that makes Coke 
Classic so dense.]

>> "Diving Tony" Cartesian Diver (buoyancy): Place an eye dropper (dry) 
inside a two-liter plastic bottle filled to capacity with water. Show Tony 
some love and squeeze him!

See also, ...

C:\Program Files\Vernier Software\Logger Pro 3\Experiments\Sample Movies

... "Cartesian Divers" folder features a .cmbl file plus QT movie.

Google Search: which liquids are compressible?
"All fluids are compressible (that is, their density increases under 
increasing pressure) to some extent, but liquids are much less 
compressible than gases ..."

>> Logger Pro 3.4.6 "Vernier Software" folder contains file called "mass 
of pennies":

C:\Program Files\Vernier Software\Logger Pro 3\Experiments\Sample 
Data\Chemistry\mass of pennies

Display graph (only) of mass of each penny versus year coin was minted.
Q. Explain the distinct drop in average mass since 1982.
A. The composition of pennies changed (pennies made of different "stuff"). 
In 1982, the composition of pennies changed from solid copper to 
copper-plated zinc.

Q. Compare/contrast the densities of copper and zinc. Based upon the 
"pennies" graph, would you infer Zn is more or less dense than copper?
A. Less dense. [zinc (Zn) = 7.14 g/cc; copper (Cu) = 8.90 g/cc]