Here's why:

* Chemical change vs. Physical change: When ice melts, it undergoes a physical change, not a chemical change.

* Same molecules: In both ice and water, the molecules are still H₂O (two hydrogen atoms bonded to one oxygen atom). The chemical composition remains the same.

* Spacing and movement: The difference lies in how the molecules are arranged and how much they move. In ice, the molecules are tightly packed in a rigid, crystalline structure. In liquid water, the molecules are more loosely packed and can move around more freely.

Think of it this way: Imagine building a block tower with LEGOs. You can rearrange the blocks, but the individual LEGO pieces themselves stay the same. Melting ice is similar – the water molecules are just rearranging their positions.