If you mix dry ice and water, you can make fog come out of a carved pumpkin. That’s great if you have dry ice, but it’s not always easy to get or keep for when you need it. A similar cool option is to burn a smoke bomb inside a pumpkin. If you use a homemade smoke bomb, you get smoke (great for daytime effects) and also purple flames (perfect for night). Here’s how to make a smoke bomb Halloween jack o’ lantern.
Smoke Bomb Jack o’ Lantern Materials
Well, obviously you need a pumpkin. Use a real one, as plastic could melt. Also, please carve it. A smoke bomb needs air to burn. It also needs space to vent the smoke, flame, and gases.
You also need two chemicals:
- Potassium nitrate
Basic granulated sugar works great. Potassium nitrate can be purchased by its chemical name online. It’s also available in certain household chemicals in pure form. I used Spectracide stump remover. Check the label of your product. You want to see “potassium nitrate” or “saltpeter” and nothing else. At a minimum, it needs to be the first ingredient. The potassium nitrate makes it easier for the sugar to burn. The potassium ion burns with a characteristic violet flame.
Make the Smoke Bomb
The classic recipe calls for 3 parts potassium nitrate to 2 parts sugar. For example, you could mix 1-1/2 cups potassium nitrate and 1 cup sugar or 3 cups potassium nitrate and 2 cups sugar. There are two ways to mix the ingredients.
- You could mix them together in a bowl with a small amount of water. Shape the “dough” into smoke bombs and allow them to completely dry.
- You can mix the ingredients together in a pan over a warm stove. The ingredients melt together into a mixture that resembles caramel. The result is sticky, so it’s best to transfer it to a sheet of aluminum foil to let it harden.
The ratio between the ingredients can be changed to make either more smoke or else more purple flame. Mixing equal amounts of potassium nitrate and sugar makes a smoke bomb that is a bit harder to light, but produces more smoke. If you add more potassium nitrate (say, 2:1 potassium nitrate to sugar), the resulting smoke bomb produces less smoke but a lot of purple flame. You can also add a bit of baking soda to the mixture to moderate the reaction.
Take your smoke bomb and place it inside a dry carved pumpkin. Use a long-handled lighter to ignite it and enjoy the show!