My high school chemistry teacher was most entertaining when he was angry. He liked to quiz us individually in front of the whole class.
“What’s the Avogadro constant?” he asked one of the girls.
“Six point zero two times ten to the power of thirty-two,” she replied.
“Wrong! Failed! It’s six point zero two times ten to the power of twenty-three.”
“But I was so close!”
“Close? You missed by eleven orders of magnitude! I’d have passed you if you’d have said something like ten to the power of twenty-three, but your answer was way off.”
He got angry about recycling too. “Everyone thinks paper bags are better for the environment than plastic bags, when it’s the other way around,” he declared. He was probably right about that too. Alex Chalmers on Works in Progress has a good article about when recycling makes sense and when it doesn’t. A case can be made for recycling metals such as aluminum, but for other materials, recycling only feels better but doesn’t make environmental or economic sense.
So what about paper vs plastic grocery bags? Turns out my chemistry teacher was right. Plastic bags require less energy and water to make and have lower greenhouse-gas emissions.
Nehaveigur 