This is the cake I made for his 9th birthday party, we had a Mad Scientist theme. I had 10 little boys on my back deck mixing vinegar with Bi-Carb soda and watching the chemical reaction. They also mixed cornflour and water then held it in there hand and rubbed it into a ball then stopped to have it ooze out between their fingers. Everyone had a great time and surprisingly they were not to dirty at the end of it all.
I will try to find some more photos of Liam' birthday parties to post on here for next time.