As an illustration, imagine standing in a crowded gymnasium with each person holding an empty glass. There is a sink on one end of the gym and someone at the opposite end wants a drink, but because the gym is so crowded no one can move. The person nearest the sink can fill their glass with water and pour it into the glass next to them. This process could continue until the water is passed across the gym. This is similar to the Sun's energy being passed from atom to atom until it reaches the end of the radiation zone.
One important difference between our analogy and what takes place in the Sun
is that in the gym we would pass the water in such a way that it always moves
towards the other side. The atoms in the Sun do not do this. Infact,
there is no direct communication between one end of the radiation zone
and the other. Instead, the Sun's energy is passed randomly from atom to
atom. Sometimes it moves
outward, sometimes inward and just a often it moves side to side. It takes
over 170 thousand years for the energy released in the core of the
Sun to get out of the radiation zone!