A college professor stood before his philosophy class at the start of a new semester. Silently, he picked up a very large jar and filled it with golf balls. Then he asked the students if the jar was full. They agreed that it was.
The professor then picked up a box of pebbles and poured them into the jar. He shook the jar lightly, pebbles settling into the open areas between the golf balls. He then asked the students again if the jar was full.
They agreed that it was.
The professor next picked up a box of sand and poured it into the jar. He asked once more if the jar was full. The students again responded with a resounding “yes.”
The professor then produced two beers from under the table and poured them into the jar, filling the empty spaces between the sand. The students laughed.
