We use units of weight to tell how heavy or light something is.
It's hard to know the weight of a thing if we just say "as heavy as a sack of flour".
... or "like the weight of a stack of books".
That's why we use units of weight.
Units of weights, like the pound or kilogram, are weights that everyone agrees upon.
⚖️ Everyone agrees exactly how heavy 1 pound is.
In this lesson, let's learn about the units of weight in the US customary system. In the next lesson, we'll cover the metric system.
The units of weight in the US customary system are ounce, pound, and ton.
Tip: The US customary system is used just in the United States. 🇺🇸
Ounce is the smallest unit of these three.
A pencil weights 1 ounce.
A can of soup can weight 1 pound.
1 pound = 16 ounces
This loaf of bread also weighs 1 pound.
A small car weighs about 1 ton.
1 ton = 2,000 pounds
Tip: The US customary ton is also called a "short ton".
Units of weight are usually written using abbreviations, or shortened forms.
ounce or ounces - oz
pound or pounds - lb
ton or tons - T
Yes, this one is capitalized!
Tip: Don't add "s" to "lb" even when you have more than one. The abbreviations are the same for singular and plural.
The word pound comes from the Latin words "libra pondo", which mean "weight by pound".
The acronym "lb" comes from the "libra" part of "libra pondo", even though the full name, "pound", doesn't have "libra" in it anymore. 🤯
This football weighs 1 pound.
We can also say that it weighs 16 ounces.
This bag of coffee beans weights exactly 1 pound.
We can also say that it weighs 16 ounces.
This bag of apples weight 5 pounds.
It is also 80 ounces.
This black rhinoceros weighs 1 ton.
It's about 2,000 pounds.
1 pound = 16 ounces
1 ounce = 1/16 pound
1 ton = 2,000 pounds
Look at these measurement equivalents between pounds and ounces.
Tip: Sometimes the customary unit abbreviations have a period at the end. Usually you don't write a period after the abbreviation, but you may see it both ways.
Here's a table for measurement equivalents between tons and pounds.
You'll learn more about conversion of units of weight in the next lesson.
Great job learning about the US customary units of weight. 👏
Now, start the practice, or continue to the next lesson to learn the metric units of weight.