Science Is A Blast!

Monday, June 22, 2009

I wanted to order Aiden one of those Steve Spangler Geyser Tubes and just had not gotten around to it. Well, the other day I stumbled upon them at Michael's and for $4.95 (plus a 40% off coupon) I knew I could not resist. I was certain this mini explosion would be a big hit with him and this kit did not disappoint.

From Steve Spangler's website, here's how it works:

"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."

This is one science experiment that is a blast for kids and grown ups alike!

Sorry the video is horizontal. Damn that photographer!
Amy Dingmann said...

Finally - a great explanation to the Mentos and Diet Coke thing we did just a week or so ago. Thanks!!!

really.truly said...

I'm thinking I need to make a trip to Michael's ;) Great deal and great find!

Laurie said...

Oh my gosh, your kids' reactions to it are AWESOME!! :)

Brandie said...

OMG I love Steve Spangler!

Free Sample Freak

Aimee said...

Cool! My son has been wanting to do this experiment ever since he saw it on tv.

Steve Spangler said...

Who would have thought that dropping Mentos into a bottle of soda would be this much fun. I'm glad the explanation helped. Great video!

Susan Wells said...

This is great! I think the most popular thing to say after a Mentos Geyser is "do it again!"

Steve recently explained how the Mentos/Coke reaction is physical by experimenting with smooth Mentos and debunking a popular hoax -

Anonymous said...

last few days our class held a similar talk on this subject and you show something we have not covered yet, appreciate that.

- Kris


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