Mentos and fizz experiment

Today we conducted another science experiment using readily available household materials - Sprite, Diet Coke and Mentos mints.

We all gathered outside while Bryce opened the Sprite bottle.  We waited...... 

Samara took the paper tube with half of the packed of the mint mentos inside and lined it up with the Sprite bottle opening. She then pulled her hand away to let the mentos fall into the bottle (this was a bit tricky as it was raining and the paper had got damp so the mentos stuck to the paper!)

 And..... a little ACTION!!!!!!!!

There was a reaction with instant foaming of the Sprite up the neck of the bottle and spilling out.  It was over quite quickly though with 3/4 of the Sprite still left in the bottle.

Time to repeat the experiment with Diet Coke.  We all had to make a prediction prior to carrying out the experiment with most of us thinking that the Diet Coke would have a better reaction with the mentos mints.  

William lines up the tube of mentos with the Diet Coke bottle...

 And... ACTION!!!!!

 Check out the reaction on the students' faces!!!!

 Instantly there was a fountain of coke spurting up above the top of the coke bottle. The mixture continued to bubble inside the bottle for quite some time.

 All that was left - half a bottle of Diet Coke with mentos sunk to the bottom!

We think that there was a chemical reaction between the Sprite / Diet Coke and the mentos. The carbon dioxide (in the fizz) caused the fizz to be spurted up out of the bottle as soon as it came into contact with the mentos lollies.

What the experts say....

When we searched the internet for an explanation for how this experiment works we found out that dropping something into the fizz speeds up the process of the carbon dioxide trying to escape, because bubbles form on the surface of the Mentos.  Because Mentos lollies are covered in tiny dimples (a bit like a golf ball), this increases it's surface area and means a lot of bubbles can form.

We also found out that the experiment works better with Diet Coke than other fizzy drinks due to the different ingredients used in Diet Coke and the fact that it is less sticky.

We were left wondering........

• Would other types of lollies work so well, for example, Eclipse mints?
• Would it spurt up higher if we put the whole tube of Mentos mints into the Diet Coke?
• What would happen if we put a Mentos and some coke in our mouth at the same time?