A Liquid Interaction is one of the Portable Custom Interactions which is part of the standard TAO package.
A Liquid interaction, developed to showcase the possibilities of PCIs, contains a simple simulation of a liquid container. The container has a scale on the left-hand side. This type of interaction can be used to ask questions about volume. To record the correct answer, click on Response and then click inside the cube at the desired point. If the answer is “5 liters”, for example, click in the cube at the level of the 5 on the scale on the left-hand side, and the cube will ‘fill’ to that level with a simulated blue liquid.