The gas was placed in a heat-insulating shell. How will the gas temperature change if the volume

The gas was placed in a heat-insulating shell. How will the gas temperature change if the volume of the shell is gradually increased?

If you gradually increase the volume of gas in the heat-tight shell, then the gas temperature will decrease. This is due to the law of conservation of energy. The energy density before expansion had one meaning. After expansion of the gas, it is logically clear that the energy density should decrease, corresponding to the expansion of the volume. And the gas temperature decreases due to the decrease in the energy density. The law of conservation of energy works always and everywhere, no matter what anyone says.