Mastermind Toys 龍捲風管

My kids were mesmerized watching the water spin into a funnel shape—it's such a simple but effective connector. The tube fits standard soda bottles perfectly and creates a really impressive vortex every time.

Made a tornado in about 10 seconds with just two soda bottles and this tube – the connector seals tight enough that not a drop leaked. My kids have been mesmerized for days now.

Took a few tries to get the bottle connection watertight, but once we did the spinning vortex effect was surprisingly dramatic. Works exactly as described for a quick science demo.