One day, the chemistry teacher asked his students, "What is the chemical formula for water?"
Silly Suzie immediatelyraised her hand. "Yes, Suzie, what's the answer?", the teacher asked. Suzie answered proudly, "The chemical formula for water is 'HIJKLMNO'!" Her teacher looked perplexed. He asked, "What are you talking about?" Suzie replied, "Yesterday you said the formula for water is H to O!"