Frozen Erupting Snow. I don't think I would add the vinegar, leave it for them to play.
Indoor winter fun can be excellent on a cold, wet day. Give this experiment a try to bring the outside in while staying warm. This is even better if you research why the snow expands when vinegar hits it.
'Frozen' Erupting Snow!
Frozen Erupting Snow
'Frozen' Erupting Snow - a lovely sensory activity that your little Frozen fans will love!
MMF #6 -'Frozen' Erupting Snow :http://pagingfunmums.com/2014/07/13/frozen-erupting-snow/
Frozen erupting snow
Frozen Erupting Snow 5