This year we opted for a witch’s Bubbling Cauldron, which relies on that old trick of baking soda plus an acid (in this case citric acid) to make a bubbly explosion.
The first step was to Make the Witch of course. Travis helped fold the provided felt pieces into her cape and hat, which he decorated with spooky stickers (bats!), and which then slide onto the wooden peg body.
A pipe cleaner forms her warty nose and we added spooky features with black marker.
Next he needed to Build the Witch’s Lair. Decorate the provided backdrop with more stickers, then attach to the base with sticky foam dots.
The witch and her cauldron are then attached to the base with additional sticky foam.
An air pump is then threaded through the back of the scenery. One hose dangles down into the base, and the other dangles into the cauldron (these are helpfully color-coded red and black so your child can be sure the pump is going to flow in the right direction).
It’s time for some bubbly science! Pour the provided packets of citric acid and baking soda (colored green!) into the provided cup and mix well.
Add 4 scoops to the cauldron; Travis loved being in charge of his own “potion” here. Pour 1 and 1/2 cups water into the holes of the base, and then start squeezing the air pump…
…and marvel at the bubbling cauldron that results!
This was so cool and eerie and scientific and magical all at once. And needless to say, pretty soon there were poor Lego fellows drowning in the witch’s pot.
A definite win for a Halloween project.