What is made of water but if you put it in water it dies?

This clever riddle plays on our understanding of states of matter and a bit of personification. The object in question is, of course, an ice cube. It is entirely composed of water, frozen (Review) into a solid state. When we say it "dies" in water, we're referring to the process of melting, where the solid ice transforms back into its liquid form.

The "death" of an ice cube is a fascinating example of a phase transition. When an ice cube is submerged in liquid water, especially water that is above freezing temperature, heat energy is transferred from the warmer liquid to the colder ice. This added energy causes the water molecules in the ice to vibrate more rapidly, breaking free from their rigid crystalline structure and returning to the more fluid arrangement of liquid water. The solid form ceases to exist, effectively dissolving into the surrounding liquid.

This transformation highlights the dynamic nature of water. It can exist as a solid (ice), a liquid (water), or a gas (steam), all depending on temperature and pressure. The melting of an ice cube isn't a destruction of the water itself, but rather a change in its physical state, demonstrating the constant interplay of energy and matter in our world. It's a simple, everyday occurrence that beautifully illustrates fundamental scientific principles.