As a proud American, I am deficient in metric thinking.
For meters, I think of a football field minus 30 feet.
For a liter, thanks to Coca-Cola, I think of a liter bottle. Note: this is more or less a distinct physical memory. It is akin to my distinct physical memory of cups, tablespoons, e.g., after long experience through cooking.
But grams still stump me. Centigrams and milligrams I guess are of more intellectual interest.
Thanks,
Leo
When I was in grade school in the 1970s, and there was a big national movement for learning the metric system, I learned the mnemonic that a gram weighs about as much as a paper clip. Now that I go look at this online, there’s a lot of debate as to how accurate that is (and some discussion that a Bic pen cap might be a better mnemonic), but at least it gives a rough rule of thumb.
You can imagine a volume of water of the desired weight, along the lines of the old English-units jingle “A pint’s a pound the world around”. (Assuming measurement at sea level, of course.)
The corresponding one I know for metric units is “Wherever in the world I am, a cubic centimeter is a gram”.
100 meters is 109.4 yards, or roughly a football field (goal line to goal line) plus one end zone.
(Or, a Canadian football field, but that doesn’t help most Americans. 
)
Oh, and a gram is also approximately half a LifeSaver candy.
a U.S. dime is about 2 1/4 grams
a U.S. quarter is about 5 1/2 grams
A penny weighs about two and a half grams.
For everyday estimation purposes, 1 gram = 1 mL or 1 CC of water. 1 mL is about a fifth of a teaspoon. Of course, you don’t hold 1 gram of water in the palm of your hand…
Yeah, that’s… not helpful to Americans, thanks.
For a meter, can’t you just go with “a little bit more than a yard” ?
For a gram I always thought of it as about a paper clip’s mass.
100 grams is about a quarter pound… like a quarter pounder.
A kilogram is a litre of Coca Cola
A nickel weighs 5 grams. People use them to calibrate their scales. A 2-liter bottle of pop is about 2 kilograms. A fifth of liquor is actually 750 ml, not 1/5 of a gallon, and the liquid inside weighs 750 grams.
A meter is close enough to a yard that in news reports they are often substituted for eachother for the region the wire story is going out to.
nm
Single grams are not too useful to remember (except that 1g water ~= 1ml = 1cc).
How often do you need to measure a single gram? 1 teaspoon of table salt or water is roughly 5 grams.
You mean 100 meters. For one meter, I generally just picture a meter stick; about 10% longer than a yardstick. The average height of a man is somewhere around 1.7 meters.
A gram is the weight of one cubic centimeter (i.e. 1x1x1cm cube, or 1 milliliter) of water. That’s 1/5 of a teaspoon.
I’ve never used centigrams, but that’s just 100 grams. The weight of 100ml of water, which is just under 1/2 cup. A milligram is 1/1000 of a gram, too small for humans to have a “feel” for.
No, 1 centigram is 1/100 of a gram.
I once read that a meter is a yard plus a piece of chalk.
Not that I’m suggesting this as a practical solution, but… I had some brief experiences with certain psychoactive substances in my younger days, and while it didn’t do me much good overall, it did leave me with a useful mental image of a gram.
100 grams is a hectogram, rarely used term.
The gram is not the SI base unit of mass, which is instead the kilogram. (No, this wrinkle in the system is not especially logical).
As for “centi-”, the prefix is not actually used much apart from centimetres and, sometimes, centilitres. I think people in metric countries would scratch their heads if you started talking about “centigrams”. They use kilograms, grams, even milligrams (often used in medical/scientific contexts), but not centigrams.
Likewise, “hecto-” is virtually unknown except for the unit of land area, the hectare.
One thing I learned back in grammar school is that a Nickle weighs 5 grams – easy to remember, because it’s one gram per cent. A quick check of the Wikipedia page shows that this is still true –
nickle = 5.000 grams
You can’t get much better than that.