D. De La Matter ©2006

Are your students tired of hearing about the Mentos Fountain?
Try this dramatic variation, using the principles of Inertia and Henry’s Law.


    1. Drill a ¼” (6mm) hole in the cap of an empty 2L soda bottle. Use the bottle as support while you drill first a smaller guide hole, then the 6 mm hole.
    2. Just before the demonstration, crack the seal on a fresh, room temperature bottle of Diet Tonic Water. Release the gas as slowly as possible. When the pressures are equalized, remove the cap.
    3. Screw the drilled cap onto this bottle and place a shallow wide pan on the floor to catch the overflow liquid.
    4. Put on a black T-shirt over your clothes to avoid a fluorescent shirt distracting from the event.
    5. Obtain a 2” x 2” “whacking stick” about 30 – 45 cm long
    6. Check your goggles to be sure they absorb UV light by illuminating a sheet of white paper. Place the goggles between the source and the paper. You should see a very distinct shadow of the lenses on the fluorescent paper.
    7. Position yourself so that you are not under an electrical light or other device on the ceiling.