The world plus his dog is doing “The Mentos and Diet Coke explosion”, so I thought I’d give it a try as well.
So what is happening? The Chemistry FAQ explains the mentos explosion.
Ordinarily, water resists the expansion of bubbles in the soda. Water molecules attract each other strongly, and they link together to form a tight mesh around each bubble. It takes energy to push water molecules away from each other to form a new bubble, or to expand a bubble that has already been formed. The phenomenon is called “surface tension”.
Now drop a Mentos into the soda. The gelatin and gum arabic from the dissolving candy disrupts the water mesh, so it takes less work to expand bubbles. At the same time, the roughness of the candy surface provides many little nooks and crannies that allow new bubbles to form more quickly (a process called nucleation). As more of the surface dissolves, both processes accelerate, and foam rapidly begins to form.
To repeat his experiment you will need a pack of Mentos (I used fruit) and a bottle of Diet Coke (I used a 1.5 litre one).
Make a small chute so you can slide all the mentos into the coke rapidly. I just used a flyer for blinds.
Make sure your camera team is ready…
Keep your finger over the bottom of the chute so you can release all the Mentos in one go.
Then let go!
Get out the way quickly.
Watch the Diet Coke explode.