My high school teacher says that thermal energy is the sum of the potential energy and kinetic energy, however when I asked my older brother (he is taking life science at Uni) to explain the notes he said that thermodynamic energy represents the sum of the potential energy and the kinetic energy of the molecules, and that thermal energy in this case would only represent the total kinetic energy.
Who is right? I need to do a lab on thermochem so please helpp. Im confused.