I failed with a snowball slingshot

 

I was sent this link when it had snowed in Wigton. As it happened, I did have an empty bottle and a balloon here so I hurried out to try it. Sadly, it didn't work. Two main problems - the balloons were too small and the snow was very difficult. This snow was a very fine powder. It was like trying to roll a ball out of icing sugar. I tried to improvise by filling the balloon with air.

Sadly that didn't work either and the cold seemed to perish the rubber.

Since the snow has melted and balloons are definitely a non-essential item, I'll have to wait a while to see if I can get it working properly, but the set of experiments on the website looks very helpful.