How does a microwave oven got your food hot?

Answer 1

Answer

Microwaves are electromagnetic waves, they have wavelengths ranging from mm to cm scales. The electromagnetic spectrum includes radio, infra-red, visible light and ultra-violet light waves. The waves are energy and are made up of photons (discrete packets of energy).

The wavelengths of microwaves are easily absorbed by water molecules (just like how light is absorbed by a black object).

As microwave energy is shone through food, the water molecules take the microwave (light) energy and vibrate. This increased molecular movement shows itself to us on the large scale as heat energy.

The microwaves only penetrate a few centimeters into the food before they are all absorbed by water molecules. The heating to the center of food occurs via conduction (as well as convection for fluids such as soups and sauces).

Thermal conduction is where molecules vibrate and bang in to nearby molecules - thus causing them to vibrate- and so on in a Mexican wave of heat transfer.

Molecules in fluids (liquids and gases) can move more freely than in solids- so instead of just vibrating they can also move about in all directions. As hot fluids are less dense than cold fluids (because the particles move faster and push each other further apart), so they tend to rise and cause the whole fluid to mix quite well. This convection occurs as well as conduction in liquids.
It heats up the food from the heat that surrounds in side the space during the minutes or seconds the food is in the microwave.
From what I have learnt in Physics, Microwaves heat up the water molecules within a substance and that is what heats it up. We we're told that it would heat up the food from the inside out. But that is only from a GCSE level student so I doubt someone else will be able to give a more detailed and sophisticated answer in time :-)
Radiation.

Answer 2

Microwaves are electromagnetic waves. The microwave oven generates these and directs them into the cavity where food is placed. The microwaves act on the water molecules in food, and because the water molecules are polar, they will attempt to orient themselves according to the passing microwaves. Because the microwaves are waves, they have crests and troughs, and these will cause the water molecules to "flip" continuously. This generates heat, and the heat warms the food.

Answer 3

Food is very fibrous, or less dense, in comparison to ceramic or plastics. The microwaves move very fast at a very high frequency. By doing this, they speed up the vibrations of water molecules in your food, and the faster the molecules move, the more heat is made. The dishes don't get hot, because the microvaves won't penetrate the material.

Answer 4

Microwave ovens emit microwaves at specific wavelengths. These wavelengths have specific energies that match up with the vibrational energy levels of water. When the microwave hits a molecule of water it excites that molecule of water into a higher vibrational energy state which causes the substance to heat up.(since heat energy is just the vibrational and kinetic motion of a substance)

Answer 5

Microwaves are absorbed by mainly by water and fat in the food. Microwave energy is absorb in a process called dielectric heating.

Molecules such as those of water are electric dipoles, they have a partial positive charge at one end and a partial negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field of the microwaves. This rotation makes them vibrate and the vibration of molecules is heat.

Answer 6

A microwave oven warms food by sending powerful energy waves through the food. This causes the molecules to move rapidly and heat up quickly.

Answer 7

It heats up and thaws the food that you have placed in the microwave

Answer 8

Microwaves agitate molecules into motion and collision, thus creating heat in an object.

Answer 9

Hi there It generates heat by making micro waves which cook our food by vibrating the particles and making them heat by rubbing togather.This will eventually cook our food.