What happens to resistance when temperature increases and what happens to the motion and position of a substance’s particles when it moves to a higher temperature?
When the temperature of a conductor increases, its resistance typically increases as well. This is because of two main factors:
Increased vibration of atoms: As temperature rises, the atoms in the conductor vibrate more intensely. This vibration disrupts the smooth flow of free electrons that carry current, making it harder for them to move through the material. This increases the resistance.
Electron scattering: The higher the temperature, the more frequently free electrons collide with the vibrating atoms. Each collision acts like a tiny obstacle, further hindering the electrons' movement and contributing to the overall resistance increase.
It's important to note that this relationship between resistance and temperature isn't absolute. In some special materials called superconductors, resistance actually drops to zero at extremely low temperatures. However, for most conductors, the positive correlation holds true.
Particle Motion and Position in Higher Temperatures:
When a substance is heated, the motion and position of its particles change significantly:
Increased kinetic energy: With increasing temperature, the particles gain more kinetic energy. This makes them move faster and vibrate more intensely, both within their fixed positions and by potentially changing positions altogether.
Increased spacing: In solids, the atoms vibrate around fixed positions. As temperature rises, the amplitude of these vibrations increases, and the average distance between the atoms also increases slightly. This expansion is what we experience as thermal expansion.
Phase changes: In some cases, increasing temperature can lead to a complete change in the physical state of the substance. For example, ice melts to water (liquid state) and water boils to steam (gas state) as temperature increases. These phase changes involve significant reorganizations of the particles' positions and interactions.
Overall, increased temperature leads to more energetic, faster-moving particles that occupy slightly different positions compared to their cooler state. The specific changes depend on the material and the degree of temperature increase.