5.1 - Thermal Physics Flashcards
Define Thermal Equilibrium
When the rate at which 2 objects exchange thermal energy is zero which is when they are at the same temperature.
Describe the absolute Celsius temperature scales.
2 fixed points on the Celcius scale are:
Melting point of ice: 0 degrees celsius
Boiling point of water: 100 degrees celsius
1 fixed point on the kelvin scale is:
Absolute zero 0K
Convert between Celsius and kelvin
Kelvin = Celsius + 273
Describe solids, liquids and gases in terms of spacing, ordering and motion
Solids: Atoms are very closely packed.
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Describe the simple kinetic model of matter
The ideas is that all materials can be modelled by considering the kinetic energy of the individual atoms and their collisions
Describe how Brownian motion provides evidence for the kinetic model
Smoke particles are inserted into a container of gas under a microscope
Smoke particles are seen to randomly change direction, due to the collisions with the invisible, small gas atoms
Define internal energy
Sum of kinetic energy + Sum of potential energy
Relate internal energy to absolute zero
At absolute zero, a system is at MINIMUM internal energy
Describe the relationship between internal energy and temperature
If temperature increases, kinetic energy increases and therefore internal energy ALWAYS increases
However, if internal energy increases, that DOES NOT mean that temp increases
Describe the energy transfers occurring during phase change and temp change
During a phase change, thermal energy and electric potential energy are exchanged, resulting in a change in internal energy but no temperature change as kinetic energy is constant.
During a temperature change, thermal energy and kinetic energy + electric potential energy are exchanged (materials expand / contracts as well as particle changing KE)
