When is 5 Pounds Not 5 Pounds?

At the gym, I hang a weight off my ankle to do leg lifts. I’d been using a 5-pound plate, but I wanted to increase it, so I picked up a 7.5-pound dumbbell. The thing was, it didn’t really feel any heavier. So, I picked up the plate in the other hand to compare and it still didn’t feel any heavier.

So, I took them into the locker room and weighed them. The 5-pound plate weighed 6.5 pounds and the 7.5-pound dumbbell weighed 6 pounds. I asked one of the trainers how that could be. Know what she said? Not all plates or dumbbells are accurate. I said, “Really? It can vary that much?” Yup, she said. In other words, you can’t be sure that 5 pounds is 5 pounds.

I always thought gyms paid more for some brands of weights because they looked cooler, but that’s not it. With the really good brands, the more expensive ones, you’re paying for reliability. You know every 5-pound plate you buy from them will be 5 pounds. You can count on it. That is not true with less expensive brands, as my own experience proves.

I thought the whole point of measurements was consistency. A hundred hundred Celsius is 100º Celsius. If one scientist tells another the boiling point of an element is 100º Celsius, any other scientist doing the same study under the same circumstances is going to find that the element boils at 100º Celsius. If your room measures 200 square feet and you order 200 square feet of carpet, it will cover the floor completely with little or no carpet left over. A 5’7” woman wearing 3” heels will stand 6’ tall. Granted, this hasn’t been true in women’s clothing for years, but we’ve kind of gotten used to that. And that’s why I like the sizing of men’s clothes better: A 32” inseam will measure 32 inches.

But lead is lead. Every piece of lead has the same density. Its weight’s not going to vary no matter what scale you put it on. So, it’s more than a little disconcerting to me that you can’t even be sure that 5 pounds is actually 5 pounds.