Assassin's water bottle

Assassin's Water Bottle by Steve Mould & Michael Stevens — dual-chambered bottle holds two liquids, pour one at a time. Science meets stealth in one container.

You must not use the Assassin’s water bottle to store poison, despite what the name might suggest. If you did, one side of the bottle would be deadly while the other would not. The fate of the person or animal drinking from the bottle would depend on the unobserved actions of the pourer. Which is reminiscent of some thought experiment involving a cat. This bottle incorporates a cat head design which is half white, and half black - half dead, and half alive. It also has the Steve Mould, Vsauce and Curiosity Box logos.  Each side can hold up to 450ml of liquid, with a combined volume of 900ml. 

When demonstrating the magic trick we recommend you cover the bottle with a sleeve to hide the two compartments.