Final answer:
When heated, a sphere is most likely to expand because the particles making up the material move more rapidly and occupy more space, leading to an increase in the object's volume.
Step-by-step explanation:
When a sphere is heated, it is most likely to undergo expansion. This phenomenon occurs because, as the temperature increases, the particles making up the sphere move more rapidly, causing them to take up more space. According to the principles of thermodynamics, heat moves from a region of high temperature to a region of low temperature, causing the material to expand in all directions. The high temperature side expands, which may compress the cooler parts, but as heat continues to distribute evenly, the entire sphere will eventually expand. This concept is depicted in Figure 13.11 where the expansion of an object's area and volume with increasing temperature is shown.
Expansion is typical for most materials when heated, with few exceptions. An increase in temperature typically results in an increase in the volume of the substance, whether it's a solid, liquid, or gas, barring any phase changes that may occur at certain temperatures, such as turning into a gas (evaporation) or becoming a solid (solidification).