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Hi, I'm Anders Liljeholm.
You may remember me from such videos as the egg basketball bounce and the tornado of fire.
Today we're going to talk about mentos and soda.
You've seen this reaction before. It's awesome...
[Cheers and applause.]
Now we're going to talk about the science behind it.
We're going to look at how different factors affect the way that soda explodes.
As you probably know, this is a reaction based on carbon dioxide gas.
When you drop the Mentos into the soda, all the carbon dioxide bubbles come out of the soda all at once, it foams up and shoots out of the bottle.
You can combine this with your favorite dry ice demonstration.
You can make quarters scream, put out fires, and make a liquid change from neutral to acidic.
Now, it turns out that the acidic quality of carbonated water is delicious to us, which is why we put bubbles of carbon dioxide gas into our beverages.
That's the connection between dry ice and this demonstration.
Different kinds of soda also react differently to the Mentos.
As the Mythbusters showed us,
different ingredients in the soda enhance the reaction.
This is just plain carbonated water without any additives except the carbon dioxide,
and that's not much of a reaction.
When we add in flavoring and sugar,
it gets a little bit more exciting,
but we know that if we add the diet sweeteners
then it gets a lot more energetic.
And it gets really good when you add in caffeine.
And as hundreds of middle school science projects have shown, the most explosive soda to combine with Mentos is Diet Dr Pepper.
This is also a great demonstration about how amounts of surface area of a substance can change the way it behaves.
The reason that Mentos make all the bubbles come out of the soda is because Mentos are microscopically rough.
They're covered with millions of tiny pits and bumps, places where the bubbles can form.
To show that, we're going to put other substances with surface area into the soda.
This bottle's getting Mentos,
this one's getting sand,
this one's getting iron filings - little tiny bits of iron,
and to show you that it's surface area, we're going to drop an iron bolt into this one.
It's iron, but it's one big chunk instead of lots of little pieces.
So, here we go! Iron...
Iron filings...
Sand,
and Mentos.
Another factor that has a big impact on how much the soda explodes is the temperature of the soda.
This is because temperature affects how much carbon dioxide you can dissolve in the liquid.
So here we go! This bottle has been chilled and refrigerated.
This bottle is at room temperature, and this bottle has been sitting in hot tap water for the last hour.
Cold...
Room temperature...
Hot!
It's still raining soda!