Bought for my 3 and 4 year old boys. We made filled the mold and then watched the National Geographic documentary on volcanoes to keep them interested. Here are some notes that made our experience better:
1. It is a 2-day project so tell kids in advance. Day one is making and setting the plaster in the mold; day two is for painting and eruptions.
2. Chamber - rub Vaseline around all bits of the chamber so the plaster won't harden to it. It is a super easy solution that makes the chamber removable and thus reusable many times. (Remember in grade school covering your face with Vaseline to make a plaster mask for your parents? Right, same idea here.) After about 20 minutes simply give the chamber a tug and slide it out before the plaster completely dries and hardens (over night). The Vaseline keeps it from sticking.
3. Use twice the baking soda and vinegar as suggested or the eruption is underwhelming.
4. Use food color instead of paint in the chamber mixture. Paint doesn't dissolve as uniformly at all.
5. Remember it is a small mold - roughly producing a 6" volcano - so don't expect a centerpiece for your table. The smaller size, however, makes it extremely manageable! We set ours in an 8x8 baking pan for the eruptions for easy clean-up.
Good luck. The kit is a WONDERFUL value.
Mold your volcano, paint it to look real and allow to dry. Add vinegar and baking powder and watch the volcano erupt.