Make a vortex
Make a water vortex by connecting two plastic bottles with tape, filling one with water, then swirling to observe the spinning funnel and flow.
About this activity
Make a water vortex by connecting two plastic bottles with tape, filling one with water, then swirling to observe the spinning funnel and flow.
What you need
Step by step
- 1
Step 1
Remove the caps from both plastic bottles.
- 2
Step 2
Fill one bottle about two-thirds full with water.
- 3
Step 3
Add a few drops of food coloring or a pinch of glitter to the water and gently swirl to mix (optional).
- 4
Step 4
Stand the other empty bottle upright on a flat surface.
- 5
Step 5
Hold the filled bottle upside down and place its mouth directly onto the mouth of the upright empty bottle so the two mouths meet.
- 6
Step 6
Press the two bottle necks together firmly so they sit flush.
- 7
Step 7
Wrap strong tape tightly around the joined necks at least three times to make a snug seal.
- 8
Step 8
Hold the taped seam with both hands so your thumbs and fingers grip the bottles near the join.
- 9
Step 9
Give the top bottle a quick circular swirl for about five seconds to start the water spinning.
- 10
Step 10
Watch the spinning funnel form and see the water flow from the top bottle into the bottom bottle.
- 11
Step 11
Share your finished water vortex on DIY.org
Fun facts
How do you make a water vortex with two plastic bottles?
To make a water vortex, remove labels and rinse two clear plastic bottles. Fill one bottle about two-thirds with water and add a few drops of food coloring or glitter if you like. Invert the empty bottle on top, aligning mouths, then tape securely around the seam or use a bottle-connector. Flip the connected bottles so the full one is on top, swirl in a circular motion to start a spinning funnel, and watch the vortex as water drains.
What materials do I need to make a bottle vortex?
Materials: two matching clear plastic bottles (1–2 liters work well), strong duct tape or a commercial bottle-connector, water, and optional food coloring or glitter for visibility. A funnel helps pour water without spills, plus a towel or tray to catch drips. For safety, have scissors on hand to cut tape and supervise younger children. Avoid glass bottles.
What ages is the bottle vortex activity suitable for?
This activity suits ages 4 and up with adult supervision. Preschoolers (4–6) need hands-on help fastening bottles and starting the swirl; elementary kids (7–11) can manage most steps and experiment with color or glitter; older children and teens can test variables like bottle size and water amount. Adjust complexity and supervision to each child's motor skills and curiosity, and keep small parts and loose tape away from toddlers.
What safety tips should I follow when making a water vortex?
Safety tips: always supervise, especially with young children. Tape the bottle seam very securely or use a connector to prevent leaks. Do the experiment over a sink or on a towel to catch spills. Avoid glass, and don’t use tiny beads that could be choking hazards. If you use glitter, consider washable glitter or food coloring to reduce mess and ingestion risk. Dry and recycle bottles responsibly after the activity.
Watch & Learn
Need help?
What can we use if we don't have the 'strong tape' or food coloring listed in the materials?
Use duct tape or packing tape wrapped tightly around the joined bottle necks instead of 'strong tape,' and substitute a few drops of washable paint or a small splash of colored juice for the optional food coloring.
My bottles leak or I don't see a vortex—what should I check and fix?
Ensure both caps are removed, the two mouths sit flush as in step 5, press the necks firmly together, rewrap the seam at least three times with tape, grip the seam with your thumbs, and give the top bottle a quick five-second circular swirl to start the funnel.
How can I adapt this activity for different age groups safely?
For toddlers have an adult do the taping and hold the bottles while the child watches and helps swirl, for school-age kids let them tape and perform the five-second swirl themselves, and for teens challenge them to make a longer-lasting vortex or improve the seal.
What are simple ways to enhance or personalize the vortex project?
Decorate the bottles before assembly, add glitter and different food-color combinations to change the funnel's look, tape a small LED to the base for light effects, or use a commercial 'tornado tube' connector and time your vortex to share on DIY.org.