The statements that best describe conduction are
-Conduction can occur within a substance or between two substances.
-Fast-moving molecules collide with slow-moving molecules.
-Thermal energy is transferred from a warmer substance to a cooler substance.
Explanation :
-Conduction can occur within a substance or between two substances.
Conduction can occur within a substance, but the heat will transfer by conduction only when those parts of the substance are at different temperatures.
For example, when we hold a metal rod over a flame, the end which is in direct contact with the flame becomes hot first. As we continue to heat, the other end of the rod also becomes hot because heat gets transferred through the rod by conduction.
Similarly heat can also be transferred between 2 substances which are in direct contact with each other.
In the above example, when a person is holding the other end of the rod, their hand might burn. In this case heat is transferred between 2 objects ( rod & hand) which are in direct contact by conduction.
-Fast-moving molecules collide with slow-moving molecules.
When an object heated, the molecules gain thermal energy and start vibrating. These vibrating molecules transfer their kinetic energy to neighboring molecules which are at lower temperature and hence are slow moving. This transfer occurs till both of them attain the same temperature.
-Thermal energy is transferred from a warmer substance to a cooler substance.
Thermal energy is always transferred from a warmer substance to a cooler substance. In conduction mode, heat is transferred by transfer of kinetic energy from fast moving molecules to slow moving molecules.
