News reporters seem to have some difficulty reporting the size of things. In order to make things more accessible to their readers, they try to compare it to the size of an everyday object, but to me it seems they try a bit too hard. For example, this story about the recent rescue of the crew of a sunken submarine noted,
[T]he layers of stretched nylon appeared to be as thick as a 1 1/2-inch cable.
"As thick as a 1 1/2-inch cable". As opposed to "as thick as a 1 1/2-inch stick" or "as thick as a 1 1/2-inch thing that is about 1 1/2 inches thick". May I humbly suggest, "The layers of stretched nylon appeared to be 1 1/2 inches thick", or if you want to emphasize the shape, "The layers of stretched nylon appeared to form a cable 1 1/2 inches thick".
On a similar note, back in 1997, All Things Considered talked to Major Mike Morgan, deputy director of the Space Control Center, the people who track space objects 10cm or larger. Major Morgan translated this from metric to American units as follows:
That's about the size of a three-inch bolt.
Actually, 10cm is 3.9 inches; if he wanted to remain fixated on bolts, he should've said "That's about the size of a four-inch bolt." (And don't forget that a kilogram weighs about the same as two pounds of pebbles.)
On the other hand, you can sometimes miss the mark by providing too little information about an everyday object. Describing an inflatable satellite being deployed by the Space Shuttle back in 1996, the NPR space reporter said that it "grew to the size of a giant silver pie pan".
How big is a giant silver pie pan? I figure about 40cm (18in), that's a pretty big pie. (In reality, NASA says it was about 50 feet [15m] in diameter.)