Assassin's teapot for a demonstration experiment in class

In the first phase of the experiment, the opaque teapot functions as a “black box,” which creates a conflict with students’ common intuition and forces them to guess how the trick works. The subsequent introduction of a demonstration model with a translucent wall then reveals this mechanism, allowing students to visually verify the accuracy of their guesses or enabling the teacher to provide an explanation supplemented by a demonstration experiment.

Print the model using filament of any color. For the second model, set the Slicer to pause printing before completion, replace the colored filament with a translucent one, and resume printing to create a translucent wall for observing the liquids inside the chambers. Prepare two transparent containers into which you will pour water from the kettle. Next, prepare two containers with colored water; use two different food-grade dyes, which you will draw into two syringes. Use the syringes to fill both chambers of the kettle printed with colored filament.

Procedure:

1. Plug the first opening of a chamber and tilt the kettle so that water begins to flow out into the prepared transparent container.

2. Discreetly move your finger to the second chamber opening and tilt the teapot again so that water of a different color begins to flow into the second transparent container.

3. Repeat the first step, and then ask the students to explain how this is possible.

4. In front of the students, fill the teapot with a transparent front wall in the same way—one chamber with one color and the other with a different color.

5. Perform the entire experiment in the same way, but point out the detail of blocking one chamber with your finger.