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Science Fair Projects: Build a Fog Tornado

What creates the 'tornado' part is the air created by the fan, forcing said air out of the chamber while the air from the openings on the side, forces air into the chamber. The positioning of the ventilation is critical for creating this tornado-like effect. The fog comes from the dry ice.

  • How to build a fog tornado?
      • Materials:
      • A copier paper box (8 1/2" x 11")
      • A small fan (at least 3" x 3")
      • A piece of clear plastic (10 X 17 inches or 25 X 43cm)
      • A small plastic food container
      • Dry ice
      • Black paint
      • 9-volt battery


      1. First, ask your parent to help cut parts of the cardboard up with an exact-o-blade. This is a very dangerous tool and task, so make sure to involve your parents.
      2. Parents, you will cut a large rectangle in the front of the box, leaving about an inch on all sides. On that same face, you will also cut a very thin rectangle, to the left of that bigger rectangle. This will be the same height, but just a sliver in the width.
      3. Parents, on the sides and the back, you will cut the same size small sliver rectangle. But NOT the large rectangle.
      4. Parents, you should cut a small square on the top face of the box. The opening at the top should be just a bit smaller than your fan. Lastly, you should cut a large square on the bottom face of the box. The opening at the bottom should be bigger than the plastic food container.
      5. Next, you are going to paint the inside of the box with the black paint and allow it to fully dry before continuing.
      6. You should then tape the clear piece of plastic to the large rectangle your parent previously cut on the FRONT face. Make sure to not cover the slot to the left, that is for the air ventilation.
      7. Turn on the fan and place it on the top of the chamber with the air blowing upward.
      8. Place some pieces of your dry ice into the food container and add some warm water. This should start creating the fog. Make sure the container is placed at the bottom of your chamber, where the hole is cut out for it.
      9. Put your fog tornado skills to the test and try out these other questions: Can you control the tornado by covering or loosening various parts of the slots? Do different fans affect the space? Does the box size make a difference?
      10. Record your results.

      Smart Tip: Dry ice is by far the best option for this experiment, but some other great substitutes are humidifiers or fountain misters.