Advice 1: Why the need for convection

Modern ovens are equipped with so many additional equipment that we can get confused when choosing the units of household appliances. Each additional option is reflected in the price, but on what is not worth saving, it is convection, especially for discerning Housewives.
Why the need for convection
Convection is a special way of warming up in the oven, which uses a built-in fan. It ensures the free movement of air throughout the space of the oven, causing the temperature of the far wall and the doors aligned. To understand how convection affects the cooking in the oven, it is enough to remember how grandma used to put baking pies waiting for us, when a distant browned, and changed the position of the pan that the patties are cooked evenly. Additionally, the grandmother could not put in the oven two baking trays at the same time, because the cakes are not baked. When using the oven with convection device such problems from the landlady does not arise.Of course, for the aspiring hostess, twice a year, cooking Apple pie, an oven with convection is not the subject of appliances Essentials. But for those who like to experiment and explore new recipes, this device can become a great help in the kitchen. The temperature in the oven with convection is the same in all planes, so in this case it is possible to cook several dishes simultaneously, for example, to roast meat and a side dish to it at different levels or put two or three baking trays of eclairs. Thanks to the free movement of hot air all the eclairs get equally browned and baked evenly.Essential oven with convection, and when cooking meat in an open baking pan or on a spit. Air circulation will ensure the formation of a crispy crust on the surface of the dish. But if the oven is equipped with a "grill", then these two functions running at the same time, meat dishes turn into a real gastronomic masterpieces. In addition, the convection allows you to reduce the amount of salt and oil used for cooking that is appreciated by the people leading a healthy lifestyle.

Advice 2: What is convection

The energy of motion and interaction of molecules, which compose the body, are called internal energy. The thermal motion of the particle never stops, so the body always has some internal energy. This energy can be changed (decrease or increase) the performance of work and heat transfer. There are three types of heat transfer: conduction, radiation and convection.
What is convection
Convection is the transfer of heat in liquid and gaseous environments, implemented by streams (or jets) of matter. In solids due to strong molecular attraction convection cannot occur. The energy in solids is transferred by conduction. It is well known that liquids and gases are heated from below, such as the kettle with water, put on fire, radiators placed under the Windows near the floor. The reason is that part of the substance is heated from below, expands, its density becomes less than that of the surrounding (colder) environment, and under the action of buoyancy it begins to rise. And its place at the bottom fills the cold part of the substance. After a while, progresses, this layer also rises up, giving place to the following substance flow and convection. Why liquids and gases should be heated from below heated layers cannot fall below cold.When convection energy transferred by the jets of gas or liquid.There are two types of convection: natural (free) and forced. Free convection takes place when layers of the fluid is reversed without the help of external forces, for example, the heating of the air battery in the room occurs by natural convection, but the speed of heating the water in the pot can be achieved by mixing layers of liquid with a spoon, such convection is forced. The fastest convection occurs in gases due to their loose arrangement of particles. They, being at large distances from each other, do not communicate well with each other and moved into almost independent direction, so the gases have a poor conductivity. Liquids have the middle seat between gases and solids by convection and conduction. That is, the convection they have to pass more slowly and the conductivity - faster than in gases. And with respect to solids, their thermal conductivity is weaker.
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