Mentos Geyser
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Materials:
Experiment:
This activity is probably best done outside in the middle of an
abandoned field, or better yet, on a huge lawn.
Carefully open the bottle of soda. Position the bottle on the ground
so that it will not tip over.
Unwrap the whole roll of Mentos. The goal is to drop all of the
Mentos into the bottle of soda at the same time (which is trickier
than it looks). One method for doing this is to roll a piece of paper
into a tube just big enough to hold the loose Mentos. You'll want to
be able to position the tube directly over the mouth of the bottle so
that all of the candies drop into the bottle at the same time.
Don't drop them into the bottle just yet! Warn the spectators to stand
back. Okay, you're going to drop all of the Mentos into the bottle at
the same time and then get truckin' (move out of the way... so long...
bye- bye... hasta la vista!)
It's just like fireworks on the 4th of July. The spectators erupt, of
course, in a chorus of ooohs and ahhhs. Someone yells out, "Do it
again" and you do.
How Does It Work:
Here's the question of the day... Why do Mentos mixed 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 explanation 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 heavy 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 cooking 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 artifical
sweetner, 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 a 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.
On a personal note... I've performed this demonstration well over a
thousand times - on television, talk shows, science conventions,
teacher associations, for CEO's at huge motivational speaking
rallies, for Nobel Prize winners and anyone else who might watch.
And the reaction is always the same... that's amazing! My thanks to
Lee Marek who originally shared the Mentos idea with me and to
the hundreds of teachers and science enthusiasts who continue to
share their funny pictures, videos and experiences.
Special Thanks
Thanks to http://www.stevespanglerscience.com for providing the
experiment instructions.
- A roll or box of Mentos (candy mints)
- 2-liter bottle of diet soda. Either diet or regular soda will work
for this experiment, but diet soda is less sticky when you're
cleaning it up!
Experiment:
This activity is probably best done outside in the middle of an
abandoned field, or better yet, on a huge lawn.
Carefully open the bottle of soda. Position the bottle on the ground
so that it will not tip over.
Unwrap the whole roll of Mentos. The goal is to drop all of the
Mentos into the bottle of soda at the same time (which is trickier
than it looks). One method for doing this is to roll a piece of paper
into a tube just big enough to hold the loose Mentos. You'll want to
be able to position the tube directly over the mouth of the bottle so
that all of the candies drop into the bottle at the same time.
Don't drop them into the bottle just yet! Warn the spectators to stand
back. Okay, you're going to drop all of the Mentos into the bottle at
the same time and then get truckin' (move out of the way... so long...
bye- bye... hasta la vista!)
It's just like fireworks on the 4th of July. The spectators erupt, of
course, in a chorus of ooohs and ahhhs. Someone yells out, "Do it
again" and you do.
How Does It Work:
Here's the question of the day... Why do Mentos mixed 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 explanation 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 heavy 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 cooking 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 artifical
sweetner, 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 a 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.
On a personal note... I've performed this demonstration well over a
thousand times - on television, talk shows, science conventions,
teacher associations, for CEO's at huge motivational speaking
rallies, for Nobel Prize winners and anyone else who might watch.
And the reaction is always the same... that's amazing! My thanks to
Lee Marek who originally shared the Mentos idea with me and to
the hundreds of teachers and science enthusiasts who continue to
share their funny pictures, videos and experiences.
Special Thanks
Thanks to http://www.stevespanglerscience.com for providing the
experiment instructions.