Scorched Coffee Cups

Maybe the lid deflects a wee bit of the microwave energy?

Hmmm. If so, I wonder if I pasted coffee cup lids all over my car would it be invisible to radar? Somebody get DARPA on the phone! I need a grant!

OK, apparently my first finding was flawed. I just warmed up my coffee again with the lid on like I did yesterday and this time I only did it for 40 seconds and it nearly caught fire! It was severely scorched and smoking on the bottom and somebody had to stop the microwave! I have no idea why today was any different than yesterday. Both times it was a large coffee with one milk and one mint flavour shot. My co-worker warms her large coffee every day with the lid on form 1 min. The only difference is she always has one cream in her coffee....does the milk + flavour shot make a difference. I kind of want to try it again with only one milk and no flavour shot, then at least I can narrow down the difference to milk vs. cream. Although this still doesn't explain why it didn't scorch yesterday.....I'm so confused!

I need a highschool kid to turn this into a Science Fair project!

maybe the position its placed in the microwave might make a difference. Or maybe slightly different initial temp?