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Heat can be transferred through any matter made up of molecules and atoms. At any given time, the atoms are in many states of motion. Heat energy or thermal energy is produced by the motion of atoms and molecules, and it is present in all matter. The heat energy is directly proportional to the amount of molecular movement. This means that the more the molecules can freely move, the more heat energy it contains.
What is Heat transfer?
Heat transfer refers to the movement of energy within a substance. The study and analysis of heat transfer, as well as the changes that follow it, is known as thermodynamics. Understanding heat transfer is key to understanding thermodynamic processes, such as heat engines and heat pumps.Types of Heat Transfer
According to the Kinetic Theory, the motions of atoms or molecules create the substance’s internal energy. Heat energy allows energy to transfer from one body or system into another. You can see heat transfer in many different ways.- Conduction
- Convection
- Radiation
What is Convection?
Convection is the heat transfer or mass transfer of molecules due to movement of a large amount of molecules within fluids. A fluid is defined as anything with freely flowing molecules that can readily migrate from one location to another. Fluids include liquids and gases. When heated, one of the most essential properties of fluids is that they rise. This is due to the fact that when molecules become heated, they expand out and move apart. When a fluid gets heated, its density reduces and the hot fluid rises upwards. Because cooler fluid is less dense, it sinks. Convection currents are created by this up-and-down action.The circular movements of heated fluids that help in the distribution of heat are Convection currents.Easy Explanation of Convection
Let us explain this to you in a simple manner. Imagine that you are making tea in a teapot. The milk was cold in the teapot at first. Isn’t it true that the milk in the bottom of the pot was the closest to the hot stove burner? As a result, the milk in the bottom began to heat up first. The molecules stretched apart and grew less dense as it heated. As a result, the hot milk rose to the top. The colder milk at the top sank to the bottom while the hot milk ascended to the top. Because it was closest to the fire while it was at the bottom, THAT milk became hot and rose to the top. The hot milk ascended and the cold milk sank as the milk heated up. If you look closely, you can see the milk in the pot going up and down. A convection current caused the up-and-down movement. The heat was distributed evenly throughout the milk due to the convection current. Convection currents can be used to explain why the air at the top of a room is hotter and the air at the bottom is cooler. Convection currents are the reason why the water is warm at the surface but gets colder as you swim deeper. One natural example of convection currents is: Wind. The Sun warms the air above the earth on a sunny day. As the heated air rises, so does the temperature. Cooler air moves in to take its place at the bottom as it rises. Wind is created by the movement of colder air. Because the Earth warms unevenly, wind blows all over it. Sections that are colder and parts that are warmer are constantly present. The wind moves from the cooler to the warmer portions of the Earth.Types of Convection
There are two types of Convective heat transfer:- forced or assisted convection
- natural or free convection
