Use vinegar, bicarbonate of soda and water to make a zip lock sandwich bag explode
1 (sandwich size) zip-lock bag per person/between 2 (freezer bags work best)
Bicarbonate of soda
1. Go outside - or at least do this in the kitchen sink.
2. Put 1/4 cup of pretty warm water into the bag.
3. Add 1/2 cup of vinegar to the water in the bag.
3. Put 3 teaspoons of bicarbonate of into the middle of the tissue
4. Wrap the the bicarbonate of soda up in the tissue by folding the tissue around it.
5. You will have to work fast now - partially zip the bag closed but leave enough space to add the bicarbonate of soda packet. Put the tissue with the bicarbonate of soda into the bag and quickly zip the bag completely closed.
6. Put the bag in the sink or down on the ground (outside) and step back. The bag will start to expand, and expand, and if all goes well...POP!