A group of brunettes are sitting at a bar and one of them decides to tell a joke.
"So there was this scientists convention for all of the smartest scientists in the world. A group of all blonde scientists decided to make an announcement that they were going to visit the sun. All of the other scientists break out in laughter at their stupidity. 'Whats so funny'one of them asks. 'you cant travel to the sun...its too hot!' one of them says through bursts of laughter. then the blondest scintist of them all says 'well, you are the idiots...we will go at night.'This makes the scientists laugh even more.
While all of the brunette girls are cracking up over their friends' joke, the only blonde in the bar comes up and says 'whats so funny about going to the sun? if they went at night it would be the moon, duh.' she walks away, looks back and glares. as soon as she is gone all of the brunettes fall to the ground whith laughter.
I think this justifies the term "dumb blonde"