What's the difference between traditional heating and microwave radiation?

Traditional heating uses heat conduction, or through air, or through water and other media to transfer the temperature from the outside to the inside of the object;

Microwave radiation heating is to make the water molecules inside the microwave oscillating object rub against each other and generate heat from the inside out.

Therefore, microwave has its limitations, that is, objects without water molecules cannot be heated, and metal objects cannot be heated because of microwave characteristics.