Part 1: When a lightly inflated balloon is placed in a freezer, the temperature of the air molecules inside the balloon decreases. According to the kinetic molecular theory, the volume of a gas is directly proportional to its temperature. As the temperature of the air molecules inside the balloon decreases, the average kinetic energy of the air molecules also decreases, causing the gas to contract. This contraction leads to a decrease in the volume of the gas inside the balloon, which causes the balloon to shrink in size.
Part 2: If the balloon is instead kept outside in the sun for some time, the temperature of the air molecules inside the balloon will increase. According to the kinetic molecular theory, an increase in temperature leads to an increase in the average kinetic energy of the gas molecules, causing them to move faster and collide more frequently. This increased collision frequency leads to an increase in pressure, which causes the balloon to expand in size. Therefore, the balloon will most likely get bigger when it is exposed to the heat of the sun.