Whiskey or water?

A chemistry teacher wanted to teach his 5th grade class a lesson about the evils of liquor, so he produced an experiment that involved a glass of water, a glass of whiskey and two worms. "Now, class. Observe the worms closely," said the teacher putting a worm first into the water.The worm in the water writhed about, happy as a worm in water could be.The second worm, he put into the whiskey. It writhed painfully, and quickly sank to the bottom, dead as a door nail."Now, what lesson can we derive from this experiment?" the teacher asked. Johnny, who naturally sits at the back, raised his hand and wisely, responded, "Drink whiskey and you won't get worms."