Microwave radiation is absorbed by different substances depending on their molecular structure, water content, and electrical properties. Here’s how various materials interact with microwaves:
- Water and Moist Substances:
Water molecules are polar, meaning they have a positive and negative end. Microwaves cause these molecules to rapidly rotate, generating heat through friction. This is why substances with high water content (like food) absorb microwaves well and heat up quickly. - Fats and Sugars:
These absorb microwaves, but not as efficiently as water. They heat more slowly because they are less polar, though they can still warm up in a microwave oven. - Metals:
Metals reflect microwaves rather than absorb them. That’s why metal objects can cause sparks or fires in microwave ovens—they reflect energy back into the magnetron or concentrate it at sharp edges. - Plastics and Glass:
Most plastics and microwave-safe glass are transparent to microwaves and don’t absorb them. They remain cool unless heated by contact with hot food or liquid. - Ceramics and Paper:
These absorb microwaves weakly and generally heat up only when in contact with hot food. Some ceramics may contain water or conductive materials and may absorb more energy.