Microwaves

There are limits of course. Radio waves penetrate unevenly in thick pieces of food (they don't make it all the way to the middle), and there are also "hot spots" caused by wave interference, but you get the idea. The whole heating process is different because you are "exciting atoms" rather than "conducting heat"." -- Howstuffworks.com From Wikipedia.org: "Microwaves, also known as Super High Frequency (SHF) signals, have wavelengths approximately in the range of 30 cm (1 GHz) to 1 mm (300 GHz)." and "A microwave oven uses a magnetron microwave generator to produce microwaves at a frequency of approximately 2.4 GHz for the purpose of cooking food.

Three types of heat transfers help solar cookers use the sun’s energy to cook food. Heat is always transferred from the warmer object to the cooler object. Heat is also transferred to and through some materials better than others. The three types of heat transfers are radiation, conduction, and convection. Convection is the heat transfer by movement through materials such as air or a liquid.

INTRODUCTION A microwave oven is a kitchen electrical appliance that passes an electromagnetic wave with an extremely high frequency that is used to cook food. By absorbing energy from water molecules in the food, heat is produced, and therefore cooking can be performed. Besides cooking, microwave oven can be used to warm up food as well as used to defrost frozen food. Invention of microwave ovens definitely saves us a lot time and electricity. During this week laboratory class, we have been assigned to conduct tests on various models of microwave ovens.

In 1910, Arthur Eddington, a British Astrophysicist, discovered solar winds. Solar winds are basically a continuous flow (they are never ending basically) of particles from the sun. They are also known as stellar winds. Their usual way out of the sun is the coronal holes. Their main cause is an expansion of gases in the corona, which is the outer layer of the sun.

The egg eventually exploded, but not before Dr. Spence's curious colleague went in for a closer look. As he did the the egg exploded covering his face with hot yolk! Dr. Spence, after the two experiments, concluded that the melting candy bar, the popping popcorn, and the exploded egg where do to exposure to low-density microwave energy. The First Oven... By late 1946 the Raytheon Company had already filed a patent proposing that microwaves be used to cook food. Engineers of the company went to work quickly trying to make a microwave oven for economical use.

Metal grids also cover the front door, which is made of glass, and the the light bulb cavity. Rotating turntables are also found in almost all microwaves and this helps them ensure that the food is all evenly heated. To achieve the best possible way to heat up your meals, the microwave does not use solid state devices. Instead, electron beams from tubes under the combined effect of the electric and magnetic fields that are made to curve and follow trajectories. Magnetrons are also mostly used in microwave ovens and it has changed everything.

An example of conduction would be the an ice cube melting in your hand, or touching a hot stove and being burned. Convection can be exemplified through hot air rising, cooling, and then falling. Lastly, radiation is observed through anything warmer than it’s surrounds like fire, the sun,

Microwave ovens use microwaves at a frequency of 2450 MHz. The Microwaves travel and cause the water, fat, and sugars to vibrate resulting in the food’s temperature rising. This type of energy is called Dielectric energy. This benefits the food making process and anyone who buys TV dinners. Another instance of microwaves is cell phones.

Stars also give off microwaves. Microwaves cause water and fat molecules to vibrate, which makes the substances hot. Thus we can use microwaves to cook many types of food. Mobile phones use microwaves, as they can be generated by a small antenna, which means that the phone doesn't need to be very big. The drawback is that, being small, they can't put out much power, and they also need a line of sight to the transmitter.

Others believe that the most expensive name brand for popcorn kernels must be purchased for the perfectly popped bowl of popcorn. Society today largely purchases popcorn at movie theaters or from grocery stores in the form of packaging prepared to be cooking in a microwave. Microwaves are very convenient to cook food by utilizing microwaves to heat the food. In fact an engineer named Percy Spencer accidentally discovered the use of microwaves for cooking food when the candy bar in his pocket melted while working with the technology. His first experiment was to try to cook popcorn with the microwaves.