Date: Wed, 29 Nov 2000 11:53:25 -0700

Author: Adam Beehler

Subject: Re: 3rd Grade

Post:

I have taught classes on matter and energy to this age group before and
here are some of the things I have tried. I realize that not all of these
ideas will make complete sense, so do not hesitate asking me for more
details.

Matter
---------
- build atoms and molecules out of ordinary items (pipe cleaners, styrofoam
balls, popsicle sticks, etc.); they do not understand microscopic structure
well
- the number one ingredient of matter is "nothing;" give them cups, water,
and sponges to see that a sponge, which looks solid, is actually full of a
bunch of holes; this age group enjoys fun contests, so have them see who
can tranfer water from one cup into an empty one with the fewest
"sponge-ings"
- demonstrate this same principle with "Waterlock," or sodium polyacrylate,
which is better known as the "baby diaper polymer;" it's a powder that
absorbs A LOT of water
- how much sugar can you CAREFULLY dissolve into a cup of cold water filled
to the brim? how about if the water is now hot?
- now that you have sugar dissolved in water, you could use this to form
crystals on something suspended in the water (you'll have to wait weeks)
- discuss the periodic table; how many elements are solid at room
temperature and normal pressures? how about liquid? how about gas?
- have students act like gas particles inside a "container;" what will
they do if they get heated up? cooled down? more or less particles in the
same space? same particles in different space?
- liquids take the shape of their containers (use glasses, balloons, etc.)
- kids like the sound of PLASMA; bring in a "plasma ball" (one of those
commercial gas-filled lightning spheres) and discuss it
- liquid crystals are one of those things "stuck" in between phases;
investigate those liquid crystal temperature strips, watch displays,
calculator displays, video game displays, etc.)
- non-Newtonian fluid is cool; someone already mentioned this idea, it's
the cornstarch and water mixture
- I have "recipes" for various types of mixtures to represent different
forms of matter (rock candy, goop, green slime, oobleck, rainbow stew, gak,
playdoughs, clays, etc.)

Phase Changes
------------------
MELTING
- give all of them an ice cube and tell them to do whatever the want
(within reason) to melt it as fast as they can; make it a contest if you
wish; then discuss the various methods and reasons why
- melt ice at lower temperature using salt
- light a candle and discuss what happens (basically, the wax melts first,
then the liquid wax evaporates into vapor, then the vapor ignites after
mixing with oxygen)
- melt something plastic to demonstrate a molecular change taking place
- hold metal utnesil over candle flame for decomposition (carbon settles
and sticks to utensil)
FREEZING
- make Kool-Aid popsicles
- play with liquid nitrogen (I agree with what was already mentioned; just
you play with it; where goggles and gloves; and have the kids back away
from you!)
- put balloon into dewar with liquid nitrogen; what happens to the rubber?
what happens to the air inside the balloon? what is air mostly made out of
(nitrogen)? have kids image that all of the air in the room were turned
into a liquid
- hammer a nail with a fresh banana; then do same thing but with a banana
that has been frozen in liquid nitrogen
- investigate heat packs, especially those with the little metal disk
floating around inside a fluid; when then metal disk is "clicked," enough
energy is given to the fluid so that it solidifies and gives off heat in
the process
- make homemade ice cream with liquid nitrogen; I've done this a lot and it
tastes great; I've got a recipe if you're curious
EVAPORATION
- boil water with and without salt
- superheat water in microwave, pull it out, and then add a pinch of salt
to boil
- investigate a "drinking bird"
- use the liquid nitrogen balloon again
- expand balloon with either dry ice or liquid nitrogen in a flask/bottle;
or simply put dry ice in a zip-lock bag
CONDENSATION
- investigate fog with either a fog machine, a "cloud in a bottle"
(isopropyl alcohol in bottle put under pressure with a pump cap and then
released; or just use a match), even use dry ice to simulate fog, or an
ultrasonic humidifier (kids love this one)
- breath onto a mirror
- make fog on the side of a glass of ice water
- implode a pop can (boil a little water in can to fill inside of can with
steam so that when the can is quickly turned upside down in container of
water the steam will condense)
- boil water in flask, remove from heat, place balloon over neck and push
down inside bottle, then watch balloon get pushed into bottle further
(steam condenses)
- use the liquid nitrogen balloon again
SUBLIMATION
- dry ice is the way to go
- blow over it
- hold some between tongs and squeeze
- put some in a ziplock again
- definitely put some in a huge container of water
- add some bubble solution (or just soap) to the water
- make Kool-Aid or something with dry ice in it (kids can "taste" the
bubbles/carbonation)

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