It was very cold on the morning of the bazaar. After the incident in September when sunlight on balloons put in so much energy that the balloons burst, I was interested to see what happened. This time, thermal energy should cross the system boundary into the surroundings, reducing the internal energy of the particles. For a gas, internal energy is the sum of the kinetic energies of the particles. The particles would have less kinetic energy so less frequent and softer collisions with the rubber and reduced pressure. That didn't happen. The balloons remained as they are pictured. However, the sun did start to shine on the balloons so that would put energy back into the system.
