Why do microwaves heat honey so fast?

[Jon M]

I've noticed that honey reaches a boiling point quicker than the same amount of water. I've melted a few plastic honey containers before I learned my lesson.

Physics-wise, why is that? I thought a microwave oven targeted water molecules. I know honey is mostly water, but why does it heat up so much faster?

 

[turbo]

Hadn't noticed that, but it might be that water can release excess heat more easily - water is a low-viscosity fluid that can mix via convection and flash to steam.

 

[negitron]

Honey is not mostly water, it's mostly sugars. But, microwaves don't simply heat water and nothing else; they are absorbed by any molecules with a dipole moment, including fats and sugars.

 

[Razzor7]

Honey is not mostly water, it's mostly sugars. But, microwaves don't simply heat water and nothing else; they are absorbed by any molecules with a dipole moment, including fats and sugars.

I've never really understood this. Wouldn't most molecules absorb microwaves as they're just electromagnetic radiation? Or is it that many substances are transparent to microwaves? Or is the dipole heating factor simply so much more significant that it's the only thing worth considering? Elusive third option?

 

[negitron]

It's not strictly absorption in the usual electromagnetic sense; it's called dielectric heating.

 

[marcusl]

The specific heat of honey is 0.54 to 0.60. If the number of vibrational modes were roughly comparable to those of water, then honey would heat twice as quickly as the same volume of water.

 

[mgb_phys]

Things with a lot of sugar like baked beans do seem to heat very quickly and to a higher temperature in a microwave. I've got lots of plastic dishes half melted from doing beans on toast

 

[turbo]

Things with a lot of sugar like baked beans do seem to heat very quickly and to a higher temperature in a microwave. I've got lots of plastic dishes half melted from doing beans on toast

Baked beans with bacon or salt pork (my preference) can be pretty messy in the microwave because they develop "hot spots" that pop and throw beans and juice everywhere. I have to heat our home-made baked beans on "medium" at most so that I don't have to clean the microwave.