V week needed the classic vinegar and baking soda volcano experience. When I set it up, almost everyone already knew what would happen.
There was a discussion over whether vinegar or water is the 'secret' ingredient, so we compared the smells of the two substances and all agreed vinegar was the key.
Then they took turns pouring and marveling at the eruption.
Efforts to make sand volcanoes erupt were less successful.
Sand play is still fun, even without the eruption.