The Weight of Expectations
I work at a boutique kitchenware store. We sell high-quality glass storage containers that are sold by volume (milliliters/ounces). A customer approaches the counter with a set of three glass jars.
Customer: “Excuse me, I need to return these. They’re faulty.”
Me: “I’m sorry to hear that! Are the seals not airtight, or is there a crack in the glass?”
Customer: “No, the glass is fine. But they don’t hold what they say they hold. The label says, ‘500 grams,’ but I can only fit about 300 grams of my protein powder in there.”
Me: “Ah, I see the confusion. These are actually 500 milliliter jars. That measures the volume, the space inside, rather than the weight of what you’re putting in it.”
Customer: “Right. 500 milliliters. Which is 500 grams.”
Me: “Well, that’s only true for water. Since protein powder is very fluffy and light, it takes up a lot of space but doesn’t weigh very much. It’s like how a bag of marshmallows takes up more room than a bag of lead sinkers.”
Customer: “I don’t want to fill it with lead. I want to fill it with powder. Are you telling me your jars change size depending on what I put in them?”
Me: “No, the jar stays the same size. The powder just takes up more space because it’s full of air.”
Customer: “Exactly! So, you’re selling me a jar that’s full of air? Just give me the refund. I’ll go to the shop next door; I saw they have ‘one-liter’ jars. Hopefully, those ones aren’t as stingy with their grams as yours are.”
