However, when a real gas (as differentiated from an ideal gas) expands through a throttling device, the temperature may either decrease or increase, depending on the initial temperature and pressure. For any given pressure, real gases have a Joule–Thomson inversion temperature[6] [7]above which the J–T expansion causes the temperature to rise, and below which the J–T expansion causes cooling. For most gases at atmospheric pressure, the inversion temperature is fairly high (above room temperature), and so most gases at those temperature and pressure conditions are cooled by the J–T expansion