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Thermal processes - Coggle Diagram
Thermal processes
Heating by conduction
Conduction only mainly appears in solids and energ through collisions of non-metals or collisions of particles and movement of electrons in metals
Conduction in liquids dont happen often as the space between each particle is somewhat distance and more mobile which makes it harder to transfer energy through direct collision with other particles
When you place a plastic spoon in a cup of hot water, the part of the spoon that is in the hot water becomes warmer faster than the part of the spoon that is not in hot water
At the start, only the bottom of the spoon becomes warmer
Particles at the bottom of the spoon gain kinetic energy. Thus, they vibrate mroe vigourously
They collide with neighbouring particles and this causes the neighbouring particles to also vibrate more vigorously and collide further with their own neighbouring particles
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During conduction in a solid, the solid atoms do not physically move from hotter region to colder region
If we use a metal spoon instead of a plastic spoon, we will observe that the whole spoon becomes warmer faster
At the start, only the bottom of the spoon becomes warmer
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Heating by radiation
Radiation occurs in all matter and transfers energy through electromagnetic waves without the need for particles to carry out energy.Thus it does not require a material medium to transfer energy
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The sun is about 5000 degree celcius and electromagnetic waves including visible and infrared light are emitted
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Heating by convection
Convection occurs in fluids(liquids and gases).It is the process where energy is transferred by convection currents due to a difference in density in different regions of the fluid
When a kettle containing water is put on a hot stove, convection currents start to circulate in the water and eventually the whole body of water in the kettle boils
At the start, the bottom part of the kettle becomes warmer
Water at the bottom becomes warmer and the distance between each molecule becomes larger, causing the water to expand, thus its density decreases
The warmer, less dense water at the bottom move upwards while colder, denser water at the top moves downwards
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Convection currents canoot move in solids as solid particles cannot move freely. They can only vibrate about their fixed positions only
Fluids usually heat up through convection rather than conduction as when molecules vibrate, they might not even hit their neighbouring molecules as the distance between each molecule is too large