I thought her explanation was pretty bad. For someone who doesn't understand the term, all she had to say was that "surface" refers to how polished or dull a ball is. "Polished" = "little surface", "dull" = "lots of surface".
Then she could have gone into why you would want little or lots of surface to cope with different lane conditions, and the racing tires analogy.
Thank goodness she had a visual. At least you could see that the "low surface" ball was polished, while the "high surface" ball was dull.
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seadrive
Cogito ergo bowl