Vortex rings with a bottle : Fizzics Education


Vortex rings with a bottle

Vortex rings with a bottle

Follow FizzicsEd 150 Science Experiments:

You will need:

  • A fog machine
  • A soft drink bottle (try different sizes!)


A fog machine next to a plastic soft drink bottle on a desk

Warm-up your fog machine and then fill your soft drink bottle with stage fog. That’s it, you’re ready to go!


Gently squeeze the soft drink bottle in short bursts… you should see a vortex fog ring shoot out of the opening!

3 A television screen showing a distance educator running science experiment with a bell jar, vacuum pump and a cup of water. There is an inset of a remote class on the screen and a video conference camera on top of the television.
Live remote classes with experienced distance educators

Discover >30 virtual workshops designed to engage students isolated at home.

  • Direct curriculum links
  • Up to 30 homes can connect together.
  • Live classes – students can question & answer our educators and participate in experiments using household materials
  • Simple connection via one-click connect
  • Based on 10 years of distance education experience & global best practice

Multi-award-winning distance classes available to keep up student enthusiasm & enrichment!

orange arrow Read more button

What is going on?

We love toroidal vortices! The way these rings form is due to the air rushing out of the bottle opening at different speeds. Think about what the air is doing as it travels out of the bottle; the air is being forced out of the bottle and some of this air is hitting the sides of the bottle opening. The air hitting the side of the bottle slows down due to friction, meanwhile, the air in the middle of the opening continues to leave the bottle at speed. The different air speed forces the ring-shape to form!

The underlying reason for the ring shape is due to a pressure differential. The mathematician Bernoulli found that moving air has less pressure than air that is still; this means that the fast air coming out of the bottle has a lower pressure than the slower air near the bottle sides. As high-pressure air moves towards low-pressure air, squeezing the bottle forces air to quickly form a ring as it leaves the bottle due to the low air pressure of the fast air rushing outwards.

Want to make larger fog rings?

Learn how to make large ones with a bin

Variables to try

  • Try different sizes of plastic bottles.
  • Does placing a triangle shape in the bottle opening create a triangle-shaped ring?

Learn more!


Leave a Reply

Your email address will not be published. Required fields are marked *

This website uses cookies to improve user experience. By using our website you consent to all cookies in accordance with our Cookie Policy.