<u><em>When balloon filled with the helium gas is left in the car at night along with the decrease in temperature the size of the balloon will get smaller or it will look like little deflated</em></u>.The above observation can be explained on the basis of Charles law:The law states that 'under constant pressure ,the volume occupied by the gas is directly proportional to the temperature of the gas'. (At constant pressure)Temperature desecrate volume will also decreases and vice versa.So, with decrease in temperature at night the temperature of the gas in the balloon will also get decreased due to which the volume of the balloon will also get decreased.
