* No new substances are formed: When butter melts, it's still composed of the same molecules (fats, water, milk solids). The arrangement of those molecules changes, but their chemical composition remains the same.

* The change is reversible: You can solidify the melted butter back into its original state by cooling it down.

* No chemical bonds are broken or formed: Melting is a change in the state of matter, not a change in the chemical makeup of the substance.

In contrast, a chemical change involves:

* Formation of new substances with different properties.

* Breaking and forming of chemical bonds.

* Irreversibility (or difficult reversibility) of the change.

Let me know if you have any other questions!