OK...let me explain it better...Voters are going to rank someone or something on a scale of 1 to 5. One being they really like and five being they really dislike.
Now image a graph where the X-axis (horizontal line) is numbered 1 - 5 across the axis. And a Y-axis (vertical line) showing the number of voters casting their vote.
In a "love'em or hate'em" proposition, a lot of voters really liking (1) a lot of voters really disliking (5) and very few in between (3), the point for 1 would be high on the graph, 2 would be a little lower, 3 would be the lowest, 4 would begin to skew upward, and 5 would be high pretty close to the level of 1.
Now draw a line to connect the dots...and WALLA!!!!!...guess what...you get a bell shaped curve!