Mentos and Diet Coke eruption

We did a Diet Coke and Mentos eruption in the garden this week. This even has its own Wikipedia page, which was useful in explaining why the reaction happens. We read the page and watched a couple of examples on YouTube before taking ours out into the garden. 

We had a leftover juice bottle with a wide lid in the recycling and we used this first, having decanted the Diet Coke into it. The foam seeped copiously but gently over the sides. 

The proper Diet Coke bottle created the effect the boys had been waiting for! We discussed how the build up of pressure, combined with the small exit hole in the Diet Coke bottle vs the wide exit hole in the other bottle created an upwards spurt rather than the previous gentle foaming.

Harry and Peter rode their bikes to the local playground after this and had a great time running around. We also did some stick investigation and collection, as we have spent lots of time this week doing activities based on the book, Stick Man. We will be finishing these tomorrow so I will post them all together.