How to Make a Tornado in a Bottle

Create a mesmerizing water vortex that looks like a tornado using two plastic bottles and simple household items.

1. What You'll Need. Gather these common household items: two clear plastic bottles (16-20 oz water bottles work perfectly), water, liquid dish soap, food coloring (optional), glitter or small beads (optional for extra visual effect), duct tape or electrical tape, and a nail or sharp object to make a hole. Make sure both bottles are clean and have their caps.
2. Prepare Your Bottles. Take one bottle cap and carefully poke a hole through the center using a nail or sharp object. The hole should be about the width of a pencil - big enough for water to flow through, but not so large that it gushes out. Adults should handle this step, as sharp tools can be dangerous for children. Test the hole size by covering it with your finger and checking that you can control the water flow.
3. Set Up Your Tornado. Fill one bottle about 3/4 full with water. Add 2-3 drops of liquid dish soap to help the vortex form more easily. If you want to make it more colorful, add a few drops of food coloring. For extra visual appeal, sprinkle in some glitter or small beads. Screw the cap with the hole onto this bottle tightly.
4. Connect the Bottles. Take your empty bottle and remove its cap. Flip it upside down and place the opening directly against the cap of your filled bottle. The two bottle mouths should be touching, with the punctured cap sandwiched between them. Wrap duct tape around this connection point several times, making sure it's completely sealed and watertight. Test by gently tugging - the bottles should stay firmly connected.
5. Create Your Tornado. Hold the connected bottles so the full bottle is on top and the empty one is below. Quickly flip the whole thing upside down so the water-filled bottle is now on top. Immediately start moving the bottles in a circular motion, swirling them horizontally. You'll see the water begin to form a funnel shape as it drains into the bottom bottle. Keep the circular motion steady to maintain the tornado effect.
6. Watch and Learn. Once your tornado forms, you can stop swirling and watch the vortex continue on its own for several seconds. The spinning water creates a hollow center, just like a real tornado. When the water stops moving, simply flip the bottles again and repeat the process. The tornado should form faster each time as any air bubbles work their way out of the system.