Fred2718 t1_j2c8smr wrote on December 31, 2022 at 4:19 AM

Reply to comment by ProveISaidIt in ELI5: Why plates get too hot to touch in the mircrowave but the food can still be cold? by jerrycotton

"it remains cooler" Lol wut? It's basic thermodynamics that something cool cannot transfer heat energy to something warm.

Dishware gets hot, even more than the food, if the ceramic or glaze contains metal elements, which can absorb microwave energy. Products marked "microwave safe" do not - they are transparent to microwaves. Clear glass is almost always non-absorbing, but many glass items cannot stand the heat from the Hot food.( More precisely, they cannot stand the stresses from uneven heating and cooling.)

ProveISaidIt t1_j2c9rxx wrote on December 31, 2022 at 4:27 AM

Which part? Microwaves heat food by causing the water molecules to vibrate.

An ice cube cools your drink by absorbing the heat from the beverage. Likewise, the plate being colder, absorbs the heat from the food that is generated by the vibrating water molecules.

Fred2718 t1_j2cbvw5 wrote on December 31, 2022 at 4:46 AM

The cold plate cannot get hotter than the food by conduction of Heat from the food.
Microwave energy can be absorbed (and converted to heat) by conductive/resistive structures in metal-based ceramics, as well as water molecules in food. I should add that most ceramics suck at conducting heat, so the dish's internal heat tends to stay there.

ProveISaidIt t1_j2ccbhp wrote on December 31, 2022 at 4:49 AM

I just figured out what you meant. That makes sense. I do know that when I heat food on a Corelle plate I can take the plate from the microwave and it does not burn my hand. The food is hot and I can eat from the same plate.

When using the stoneware the plate is too hot to handle but the food is not up to temperature.

I had assumed it was drawing heat solely from the food. I have always heard you cannot put a dry plate into a microwave because there needs to be water to absorb the energy.

ProveISaidIt t1_j2dvvkx wrote on December 31, 2022 at 3:14 PM

No one said something cool can transfer heat to something hot. Cold absorbs heat.

I said as the food warms from the microwaves that heat transfers into the plate. I don't know about ceramics containing metal elements or not.

I do know that Corning Corelle is made from dufferent types of glass, as explained in the link. I have been using Corelle in microwave ovens for almost 40 years and it does not get hot the way a stoneware dish does.

I can only speak from my own experience. If I want to preheat a Corelle plate I have to put water on it as the water transfers heat into it.