LENDING LIBRARY:
YELLOWSTONE THERMAL
FEATURES
Kit Contents:
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Geyser Tubes for Mentos & Diet Coke geysers (10)
 Mentos included
Film Canisters for Alka-Seltzer and water “geysers” (20)
 Alka-Seltzer included
Coffee Filters, Markers and water sprayer for Hot Spring Craft Project activity
“Science of the Springs” guidebook to Yellowstone astrobiology sites
 Several copies included for your students to keep
Plastic Box Device for Flour Powered Supervolcano
Curriculum Guide: “Geology Rocks,” by Cindy Blobaum
Book: “Eye Wonder – VOLCANO,” by Lisa Magloff
Book: “A True Book – Yellowstone National Park,” by David Petersen
Book: “A True Book – Geysers,” by Larry Dane Brimner
DVD: Geysers of Yellowstone and Other Thermal Features, Finley – Holiday Films,
2011, 66 minutes
Museum of the Rockies
Education Department
Lending Library
600 W. Kagy Blvd
Bozeman, MT 59717
P: 406.994.5257
visitmor@montana.edu
DIRECTIONS: COKE AND
MENTOS GEYSERS
Instructions adapted from stevespanglerscience.com
1. You’ll need a 1- or 2-liter bottle of soda (you can try different sizes and brands to see
what works the best!) and an outdoor location for your geyser. Select a flat surface
on the lawn or driveway to place the bottle.
2. Open the bottle of soda and attach the
Geyser Tube.
3. Move the slider up, and put the trigger pin
into the hole at the base of the Geyser Tube.
4. Twist off the top cap on the Geyser Tube and
drop MENTOS® candies into the tube. (You
can experiment with different amounts to see
what works best!) The trigger pin will keep
the candy from falling into the soda before
you’re ready.
5. Replace the twist-on cap.
6. Warn everyone to stand back. Countdown…
3-2-1… and pull the trigger. The MENTOS will
drop and the soda will go flying into the air!
7. Pour out the remaining soda and take a look
at the MENTOS®. You can see where the soda
has eaten away at the surface of the candy.
(Perhaps using a microscope to see the
surface before and after?)
8. No need to waste the candy… they still taste
great!
What’s Happening?
Here's the question of the day... Why does mixing Mentos with soda produce this incredible
eruption? You should know that there is considerable debate over how and why this
works. While we offer the most probable explanations below, we also understand and admit
that other explanations could be possible... and we welcome your thoughts.
As you probably know, soda pop is basically sugar (or diet sweetener), flavoring, water, and
preservatives. The thing that makes soda bubbly is invisible carbon dioxide gas, which is
pumped into bottles at the bottling factory using tons of pressure. Until you open the bottle
and pour a glass of soda, the gas mostly stays suspended in the liquid and cannot expand to
form more bubbles, which gases naturally do.
But there's more... If you shake the bottle and then open it, the gas is released from the
protective hold of the water molecules and escapes with a whoosh, taking some of the soda
along with it. What other ways can you cause the gas to escape? Just drop something into a
glass of soda and notice how bubbles immediately form on the surface of the object. For
example, adding salt to soda causes it to foam up because thousands of little bubbles form
on the surface of each grain of salt. Many scientists, including Lee Marek, claim that the
Mentos phenomenon is a physical reaction, not a chemical one.
Water molecules strongly attract each other, linking together to form a tight mesh around
each bubble of carbon dioxide gas in the soda. In order to form a new bubble, or even to
expand a bubble that has already formed, water molecules must push away from each
other. It takes extra energy to break this "surface tension."• In other words, water "resists"
the expansion of bubbles in the soda.
When you drop the Mentos into the soda, the gelatin and gum arabic from the dissolving
candy break the surface tension. This disrupts the water mesh, so that it takes less work to
expand and form new bubbles. Each Mentos candy has thousands of tiny pits all over the
surface. These tiny pits are called nucleation sites - perfect places for carbon dioxide bubbles
to form. As soon as the Mentos hit the soda, bubbles form all over the surface of the
candy. Couple this with the fact that the Mentos candies are dense and sink to the bottom
of the bottle and you've got a double-whammy. When all this gas is released, it literally
pushes all of the liquid up and out of the bottle in an incredible soda blast. You can see a
similar effect when potatoes or pasta are lowered into a pot of boiling water. The water will
sometimes boil over because organic materials that leach out of the cooking potatoes or
pasta disrupt the tight mesh of water molecules at the surface of the water, making it easier
for bubbles and foam to form.
When a scoop of ice cream is added to root beer, the float foams over for essentially the
same reason. The surface tension of the root beer is lowered by gums and proteins from the
melting ice cream, and the CO2 bubbles expand and release easily, creating a beautiful foam
on top.
Next question... Why should you use diet Coke or diet Pepsi? The simple answer is that diet
soda just works better than regular soda. Some people speculate that it has something to do
with the artificial sweetener, but the verdict is still out. More importantly, diet soda does not
leave a sticky mess to have to clean up. Hey, that's important.
What's the record for the biggest Mentos fountain? My official record is an 18-foot blast that
shot up and almost took out a half million dollar, high-definition television camera. You'll
find video on-line at www.SteveSpanglerScience.com of some of our favorite eruptions.
- See more at: http://www.stevespanglerscience.com/lab/experiments/original-mentos-dietcoke-geyser#sthash.JKAAZYSm.dpuf
So, How Is This Like a Real Geyser?
Well, to make a real geyser, you need a few things:
1) Heat– Geysers are mostly made of superheated water, so you need a heat source!
The geysers in Yellowstone Park have a bubble of magma close to the surface that
heats the water. Because the water is under pressure, it can actually become
“superheated!” That means that the water in a geyser is actually much hotter than
212°F, which would be boiling if it weren’t under that pressure.
2) Reservoir – Geysers need a place to store up superheated water until it’s ready to
erupt! Underground, there are “caves” that fill up with hot water until the pressure
builds up, and then it erupts! If there is no reservoir or “cave,” water can’t build up.
Instead, the superheated water and steam escapes through a small crack, and we
have what is called a Fumarole. There are many fumaroles in Yellowstone.
3) Plumbing System (the Vent) – The Vent is another critical part of the geyser. It has to
be just the right size. If the vent is too wide, the hot water won’t erupt at all. Instead,
it just pools at the surface, and we have a Hot Spring. There are many hot springs in
Yellowstone as well!
So, are Mentos and Coke
geysers like real geysers at
all? Sort of! They both have
Reservoirs,
plumbing
systems, and vents. The hot
water and steam of a real
geyser is simulated by the
mentos. There aren’t deep
pools of Mentos and coke
under the earth, but it is still
a
cool
and
classic
demonstration.
DIRECTIONS: ALKA SELTZER
GEYSERS
1. Pull off the cap off of the film canister.
2. Fill it about halfway with water. You can experiment with just how much
water it takes to make the best geyser!
3. Drop in a quarter or a half alka-seltzer tablet and very quickly set the cap back
on. You may want to practice putting the caps on quickly.
4. Set the canister on the ground or on a pie plate with the cap toward the
ground (Actually, try it both ways and see if one direction is better than the
other).
5. BE CAREFUL! BACK UP! You’d hate to have a film canister shoot into your face!
You’ll have about 15-20 seconds before it pops!
6. Collect your film canister and do it again!
What’s Happening?
The alka-seltzer releases gas when it is dropped the water. The gas builds up pressure inside
the canister, and the cap eventually blows off when the pressure gets too high.
Alka seltzer is actually made up of baking soda and solid vinegar. When you drop it in water,
the solid vinegar turns into liquid vinegar, and the classic baking soda / vinegar reaction (e.g.
a model volcano) takes place.
So, How Is This Like a Real Geyser?
Like we mentioned before, a real geyser has three parts: Heat, a Reservoir, and a Plumbing
System. In the Alka-Seltzer geyser, we have a Reservoir, and the heat is simulated by the
tablet, and the pressure build up from a narrow vent is like having the cap on. It’s not as
similar to a real geyser as other experiments, but it’s still pretty fun!
DIRECTIONS:
HOT SPRING CRAFT PROJECT
1) Take a look at the two accompanying photographs of hot springs in Yellowstone
National Park. What do you notice about the colors? They actually go (mostly) in the
order of the rainbow from the outside in: Red at the outside, down in through
orange, yellow, greens, and then blue. Neat! This doesn’t happen at every hot spring,
just a handful of special ones in the park.
2) Take a coffee filter and spread it out in front of you.
3) Use markers to create rings of color on the coffee filter.
4) Take a spray bottle and give the coffee filter a few quick squirts in the center. The
color will start bleeding toward the outside of the filter, making your own hot spring!
What’s Happening?
The color spreads due to a process known as paper chromatography. The water spreads out,
and picks up the molecules of color as it goes along. This is used in a number of different
science applications, such as soil testing.
So, How Is This Like a Real Hot Spring?
Well, it looks like a hot spring, and you use water, haha! (See the notes for “Coke and
Mentos Geysers” for a discussion on how hot springs are formed.)
Okay, really, though, the colors are the best part of this craft. The colors in a real hot springs
are caused by very special bacteria that live in the very hot water. Most creatures can’t
survive this extreme heat, but Yellowstone is home to bacteria called “thermophiles” that
love heat and are found nowhere else on the planet. Each of the different colors is actually
home to billions of bacteria – a different kind of bacteria for each color! The colors actually
change as the temperature changes through the year. In the summertime pictures, as you
see, there are mostly orange and red bacteria, but in the winter there is more of the green
variety.
The center of the pools is bright blue because it the water is extremely pure and pretty deep
(GPS – 160 feet, MGP – 25 feet). It is too hot in the very center of these pools (about 160 °F)
even for the thermophiles.
Scientists are studying these bacteria to find out more about how life may have started on
our planet. One hypothesis is that the first life may have evolved around deep sea hot vents,
similar to the bacteria found in Yellowstone pools. Another idea is that if life can be found in
these extreme environments here on earth, we may find life like it on other worlds as well!
Grand Prismatic Spring
Can you spot the people in each image?
Which is bigger, Grand Prismatic Spring or Morning Glory Pool?
Morning Glory Pool
DIRECTIONS:
FLOUR-POWERED SUPERVOLCANO
Instructions
1) Prepare the demonstration by attaching a
balloon to the rubber tubing and placing it
in the supervolcano box.
2) Cover the deflated balloon with flour, fill
the box about half way and pack it down.
3) Sprinkle a thin layer of cocoa powder on
top of the flour. (Optional, but it looks cool
during the eruption)
4) Facilitate a brief discussion about the
magma plume that sits underneath Yellowstone National Park
5) Begin to SLOWLY pump the balloon up. The balloon will expand and push up the
flour and cocoa.
6) Ask students if they can explain what’s happening and why is this like a volcano.
7) Keep pumping the balloon until it pops! Or use a skewer or pencil to pop it, if you
prefer.
8) You can push up the tube and install a new
balloon. Bury it again and repeat!
Variation: (Takes some practice)
9) Inflate the balloon a TINY bit and then let
the air out by removing the air pump.
10) Inflate the ballon just a little bit more,
then let the air out again.
11) Inflate the balloon even more, and then
pop it or deflate it.
12) This will create an EXCELLENT visual representation of fault lines, and both the
caldera and the crater.
What’s Happening? And How is This Like a Real Supervolcano?
In a real supervolcano, the crater and caldera are formed by a collapse more than the
explosion! When a magma “bubble” pushes up into the crust, it fractures and displaces the
crust, forming ring fractures and faults (and many earthquakes). Over many thousands of
years, magma will create a chamber underground and press upward on the earth’s crust.
Our balloon is like that underground magma chamber, and the packed flour is like the crust!
Over thousands of years, the underground magma chamber (balloon) keeps pushing
upward on the crust, creating a dome. Yellowstone Park has two domes right now: Mallard
Lake Dome and Sour Creek Dome. They move up and down a few inches each year as the
underground magma chamber fills and empties of magma.
Eventually, the underground magma chamber can erupt onto the surface. A mild eruption
will just result in a lava flow across the surface, and Yellowstone Park had a lava flow 70,000
years ago. Part of the Yellowstone caldera is filled with this newer lava.
If the eruption is large enough (like in a supervolcano eruption), the chamber is partially
emptied, and then can no longer support the earth’s crust above it. The crust then collapses
down into the magma chamber, creating a large caldera or crater. This can happen both
during a large eruption or afterwards, and can collapse in stages as a series. It can be
hundreds or thousands of square miles in area!
The Yellowstone Hotspot has
erupted many times over the
past 15 million years. The most
recent eruptions were 2.1
million years ago, 1.3 million
years ago, and 640,000 years
ago. There’s no evidence that
Yellowstone is going to erupt
again any time soon, though.