Banned from Skeptiko until 15 Feb

Fell about laughing as I reached the end of this paragraph I was reading in article on Wiki about Pendulums...

Pendulums are widely used in science education as an example of a harmonic oscillator, to teach dynamics and oscillatory motion. One use is to demonstrate the law of conservation of energy.[136][137] A heavy object such as a bowling ball[138] or wrecking ball[136] is attached to a string. The weight is then moved to within a few inches of a volunteer's face, then released and allowed to swing and come back. In most instances, the weight reverses direction and then returns to (almost) the same position as the original release location — i.e. a small distance from the volunteer's face — thus leaving the volunteer unharmed. On occasion the volunteer is injured if either the volunteer does not stand still[139] or the pendulum is initially released with a push (so that when it returns it surpasses the release position).

Fell about laughing as I reached the end of this paragraph I was reading in article on Wiki about Pendulums... 

We learned this stuff in the kids' playground. It was easy to hit yourself in the teeth if you were pushing someone else on a swing and didn't stand back after a hard push.