What is Microwave Oven and how does it work ?

It's also true that frozen butter is hard to thaw in a microwave, because the bulk of the substance is oil, and the portion of water present is in the form of ice, which keeps the molecules locked up in crystal form, making oscillation more difficult.

A complete analysis of cooking efficiency depends on a number of factors, including what you are trying to prepare and the cost -- and greenness -- of your local supply of electricity, gas or other fuel.

Typically though, a microwave uses less energy to heat food than conventional ovens or ranges, because it works faster and more of the energy is focused directly on the food, versus heating containers or surrounding air.

In fact, Energy Star calculated that cooking or re-heating small portions of food in the microwave saves as much as 80% of the energy needed for an oven.

Metals reflect microwaves, whereas plastic, glass and ceramics allow them to pass through. That means metals don't appreciably heat up in a microwave oven.

However, thin pieces of metal, such as foils or the tines of a fork, can act as antenna, and the waves can arc off them, forming dramatic sparks.

Although many people believe this to be the case, microwaves actually work on the outer layers of food, heating it by exciting the water molecules there.

The inner parts of food are warmed as heat transfers from the outer layers inward.

This is why a microwave can only cook a big hunk of meat to a depth of about one inch inward.

However, there are some scientists who have dissented with this view, suggesting that other interactions between the particles may be responsible for the heating.

Microwave radiation is a form of non-ionizing radiation (meaning it can't directly break up atoms or molecules) that lies between common radio and infrared frequencies.

So it is not thought to damage DNA of living things, the way X and gamma rays do. Still, microwaves can obviously cause heating effects, and can harm or kill at high energies. That's why microwave ovens on the market must operate at or below strict limits set by the federal government.