Step 1: Materials
2. A waterbottle that fits in the pipe.
3. A plastic tube
4. Corke thing
5. Baking soda
7. Cone (not pictured, too lazy)
8. Duct tape.
(I made this before I knew about instructables so there aren't many pictures)
Step 2: Cut the pipe
Step 3: Insert cone
Step 4: Enjoy!
*Warning, you might get covered in a very nasty smelling gunk, could get in eye*