I know oil and water are heated by a microwave oven but I don't know whether it will have any affect on the rubber sole or the leather/fake-leather of a shoe. It's an odd question I know, but I haven't got the nerve to try it out for myself. 

When I put baked beans in a jug in the microwave, and switch it on, the beans warm up, unsurprisingly. If I forget myself, overestimate the time needed, then shut the door with nothing in, then nothing warms up, because nothing is in there.

Where does the excess energy go? The electricity to generate the waves is being used regardless of whether there is anything to warm up or not. I understand that the waves will vibrate molecules in food if there is food there  to warm, but what if there is nothing there to warm? I can hear the machine buzzing as it generates waves, so it is still using electricity, but what has happened to this energy?

Peter Finan

Haworth

West Yorkshire

I have been informed by my family that the love of soup is genetic for the Scots. Myself, I can take of leave it, I am confused to whether it is a main or an app.

This weekend however I popped a bowl of soup into the microwave, and after 2 minutes when I reached in to get the bowl back out I found that the bowl was so hot that I an oven glove was required to retrieve it. The contents however were only lukewarm. I am ashamed to admit that I know very little about microwave ovens, it is therefore perhaps unsurprising that I am perplexed as to why the device would heat the ceramic bowl more than it would the contents. Emperical study would suggest that some ceramics get hotter than others. What's going on here then?

Yesterday, when I opened my microwave to take out some food I'd been warming, a little cockroach was there to greet me. Inside the microwave. After shooing it out, I forgot about it.

Today, it ( or it's cousin ) was there again. What's going on?

I've heard cockroaches can survive nuclear explosions, so microwaves must be pretty tame. But can they breed  in there?

Also, would they be zapped if I leave the microwave on for a long time?  How long exactly?

After microwaving a plate of food for two minutes, when I removed the plate, I noticed a living, normal and healthy ant on the bottom of the plate.  Assuming I did not pick up the ant post microwaving -- something I am almost certain I did not -- how is it possible for an ant to survive being microwaved for two minutes?  Chiton exoskeleton?  Weird surface area effect?  Ants are from space a la Fred Hoyle? ;)

Any help is appreciated.

We heard that a bowl of Epsom salts placed near a microwave or TV reduces microwave emissions, and these cause the crystals to turn to powder over time. This sounds like an urban myth, but we tried it.

To our surprise, the salts turned to powder within a week or two. Why does this occur? Are microwaves really involved?

Arlene Dowling, Australia

(Image: grz3gorz, stock.xchng)

Occasionally when reheating broccoli and sweet potato in the microwave, what sounds like violent electrical arcing occurs if the two are in contact with each other. This results in blackened sections. What is going on?

Stephen Plevier, Hadfield, Victoria, Australia