10.2 Conduction

We can fry an egg within minutes on a pan placed in contact with a hot plate. The heat travels from the hot plate to the pan and then to the egg by Conduction.




Conduction is the main mode of heat transfer in solids.

In conduction, heat is transferred from one atom to another by the vibration of atoms.





In the diagram,
When the fixed end of the device is being heated,
point A comes into contact with point B, causing the Bell to ring

Thermal energy is transferred from a region of higher temperature to a region of lower temperature. The heat energy flows through the strip without any flow of the material itself. Such a transfer of thermal energy without any movement of the material medium is called conduction.

The tiny particals in solids called atoms and molecules. Hence when the fix end is heated, the particales vibrate violently at the fix end. These particales will then collide with their neighbouring particles making them vibrate as well. Thus, the kinetic energy of the vibrating particales is transferred from the fix end to the rest of the strip.

Hence, Molecules moves further apart as thermal energy makes them move more quickly

Objects expand as heat is obtained.

The strip is made up of 2 different metals. When it is heated, Y will bend further than X, in order for current to flow. Thus, Y is better conductor of heat as it has a faster rate of expansion.

However, if we want to make the bimetallic strip more sensitive to temperature rise, we can coil the strips into a long spiral.



Therefore,
Conduction is the process of thermal energy transfer without any flow of the material medium