Ask A Scientist Chemistry Archive

name         Anita F.
status       educator

Question -   Are there any science experiments directly related to the
fourth grade social studies curriculum that focus on The Gold Rush?
------------------------------------------------
This would be a great opportunity to talk about density, because the
prospectors who panned for gold depended on this concept to separate the
denser gold from the less dense sand.  You could use chunks of iron painted
with waterproof gold paint instead of gold, and pan for gold.  To introduce
the idea of density, you could have the students observe different types of
materials of similar size but different masses-wood, rocks, metal, a paper
memo cube, a book (a chunky baby book might be the right size), etc.  The
idea that you want to get across is that density is related to both mass and
volume (probably too abstract for them--perhaps use "how heavy it is compared
to its size").  Students should also directly observe the difference between
sand and your "gold."  You could use two small jars to do that-fill one with
sand, and the other with your "gold."  Students can see that they are the
same size but do not weigh the same.  You could put a mixture of sand and gold
in another jar and shake it until the heavier gold separates itself to the
bottom.  Now comes the fun part-let the students pan for gold-I suspect pie
pans would do it.  I think you would want have basins with water, sand and
"gold" that the students separate (could be messy, but I bet it would be fun.
I do not know if anyone has a developed lesson plan for this--I have not 
done it
and I am making it up now--make sure you try this in advance!!!!
Pat Rowe
========================================================
I do not know of any prepared curriculum, but a couple of experiments come to
mind:
1. You could mimic, panning for gold by swirling a mixture of some metal
filings and some light powder, say corn starch or flour, in a pan and
illustrating how the lighter powder can be separated from the heavier by the
swirling action. It would be nice to be able to do the real thing, but Oh
Well!

2. See if you can obtain some iron pyrite (iron sulfide) from a local "rock
shop". It is called "fools gold" because it has the luster of gold ore, but
is very hard.

Vince Calder
=========================================================
     You will undoubtedly get suggestions from the physicists to separate
dense water-insoluble material (like gold) from lighter insoluble material
(like gravel) by panning or by constructing and operating a sluicebox.
     For a chemistry exercise, I recall that the California gold rush started
with the discovery of gold at Sutter's Mill.  If I recall the story
correctly, a young man working at the mill in 1848 found a nugget in or
along the mill stream.  Nearly everyone he showed it to dismissed it as
pyrite, (FeS2) aka fool's gold.  According to the legend, a woman making
soap (by cooking lye with fat) declared that if the specimen was fool's
gold, then lye would consume it, and plopped it into the kettle.  She
returned the nugget the next day unaffected by the hot alkaline solution,
and from that point, the word travelled fast.  The story is probably on the
Internet somewhere.  This may be a little dangerous for fourth grade.  Lye
is very corrosive to living tissues before it is warmed.  Processing pyrite
may release noxious sulfide gases, and few elementary classrooms have fume
hoods.  You could also look at properties of metals (malleable, ductile,
conduct heat and electricity, shiny luster, etc.)
Tim Spry
=========================================================