B Orders of Magnitude- Gaps?

DS2C

I understand that the order of magnitude is the scale of a value expressed in the metric system. For example, 500 and 900 would be of the same order of magnitude as the both are in the magnitude of 10^2.
However in the metric system, there are "gaps" between some of the orders of magnitude. For example, it goes 10^1, 10^2, 10^3, then 10^6.
My question- is there any unit of measurement between 10^3 and 10^6? There are two unlisted orders of magnitude between these two, and it just goes from kilo to mega with no listed units or orders of magnitude in between. So there's two orders of magnitude missing. What's the reason? It seems awkward to have kilo of magnitude 3, then skip directly to mega with magnitude 6.

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anorlunda

Mentor
Gold Member
I think you are confusing two things. Order of magnitude always refers to a power of 10, as in an order of magnitude approximation.

The words used for metric prefixes (such as kilo, mega) are not units. They are merely labels.
https://en.wikipedia.org/wiki/Metric_prefix#List_of_SI_prefixes

That article says:
Application to units of measurement
The use of prefixes can be traced back to the introduction of the metric system in the 1790s, long before the 1960 introduction of the SI. The prefixes, including those introduced after 1960, are used with any metric unit, whether officially included in the SI or not (e.g., millidynes and milligauss). Metric prefixes may also be used with non-metric units.

The choice of prefixes with a given unit is usually dictated by convenience of use. Unit prefixes for amounts that are much larger or smaller than those actually encountered are seldom used.

• DS2C

CWatters

Homework Helper
Gold Member
+1

You can have values with an order of magnitude 10^5 or any power you like. We just haven't given 10^5 a special name.

Oh and it's nothing to do with the metric system. 500ft and 900ft both have same magnitude, as does 100 miles and 300 miles.

• DS2C

DS2C

I think you are confusing two things. Order of magnitude always refers to a power of 10, as in an order of magnitude approximation.

The words used for metric prefixes (such as kilo, mega) are not units. They are merely labels.
https://en.wikipedia.org/wiki/Metric_prefix#List_of_SI_prefixes

That article says:
I think I rambled a little too much in my initial post. So the orders of magnitude, as you said, are powers of 10. The metric prefixes are just prefixes and not units. For example, you can have kilowatts, and kilograms. Kilo is the prefix, watts and grams are the units. My confusion is lies in the gaps of the metric prefixes.
For example:
gram: 10^0
dekagram: 10^1
hectogram: 10^2
kilogram: 10^3
megagram: 10^6

Why is there no prefix for 10^4 or 10^5?

+1

You can have values with an order of magnitude 10^5 or any power you like. We just haven't given 10^5 a special name.

Oh and it's nothing to do with the metric system. 500ft and 900ft both have same magnitude, as does 100 miles and 300 miles.
Ok there's where I was confused. So if I have a mass of 10^5 grams, there's no special name for it, and I would just call it 100,000 grams, or 100 kg, etc?

CWatters

Homework Helper
Gold Member
Ok there's where I was confused. So if I have a mass of 10^5 grams, there's no special name for it, and I would just call it 100,000 grams, or 100 kg, etc?
Correct.

• DS2C

russ_watters

Mentor
Why is there no prefix for 10^4 or 10^5?
Because it wouldn't add a significant communication convenience to have one.

• DS2C

jtbell

Mentor
Even "deka" and "hecto" aren't very commonly used, as far as I've seen, except in "hectare." Neither are "deci" and "centi" except of course in "centimeter."

• DS2C

DS2C

Ok great thanks guys.

"Orders of Magnitude- Gaps?"

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