U.S. customary units: fluid volume
Sal discusses US customary units of volume or capacity such as teaspoon, fluid ounce, cup, pint, quart, and gallon. Created by Sal Khan.
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- How many liters are in a gallon, or how many gallons are in a liter?(54 votes)
- Just keep in mind, the gallon is a US customary unit, while a liter is a metric unit.
1 gallon = 3.78 liters
1 liter = 0.26 gallon(106 votes)
- What units are used in science in U S ? I have an impression that this units are not pricise enough correct and fixed measurements.(26 votes)
- SI units (i.e. metric units) are generally used for science in the US, certainly for measuring the mass of objects.(30 votes)
- How many teaspoons are in a gallon?(20 votes)
- Here's the answer, & my work: 3 teaspoons = 1 tablespoon. 3 teaspoons times 2 tablespoons = 6 teaspoons or 1 fl. ounce. 6 teaspoons times 8 fl. ounces = 48 teaspoons or 1 cup. 48 teaspoons times 2 cups = 96 teaspoons or 1 pint. 96 teaspoons times 2 pints = 192 teaspoons or 1 quart. 192 teaspoons times 4 quarts = 768 teaspoons or 1 gallon. There are 768 teaspoons in 1 gallon.(9 votes)
- Is there a bigger measurement than gallons?(16 votes)
- Hi, Apikaila Kanake :)
There are barrels and hogsheads.
They represents larger quantities than the gallon.
I noticed that it's better to use gallons or the metric system, because barrels and hogsheads are confusing; they express a variety of quantities depending of the context or other specifications. You can see what I'm talking about at the links bellow.
- Where did teaspoon, tablespoon, fluid ounce, cup, pint, quart and gallon come from?(7 votes)
- Most of these measurements came from ancient apothecaries who needed measurements for their medicinal recipes. Back then, they compounded the recipes in the pharmacy itself, so everyone needed the same recipe. They used pints, fluid ounces, drachms (drams), scruples, and minims. A teaspoon is about the measurement of a dram, and was an unofficial measuring unit used by these apothecaries to represent one dram. All of their measurements came from earlier Roman systems of measurement, and most of these came about because of merchants and trade.
When people want to trade things, they need to know about how much stuff they are getting. Gallons are related to the old-fashioned term bushel. People needed to know about how much a bushel was, and if they paid a certain amount of gold for a certain number of bushels, how much exactly were they getting. Quarts and gallons are primarily units of trade, and for a long time there wasn't a standard version, although a quart was always a quarter of a gallon (hence the name). For one thing, there was an "ale gallon" and a "wine gallon" because these items came in two different sized containers!
Almost all measurements from the U.S. customary system date back to the Roman Empire, pre-colonial merchants and traders, and these early pharmacists.
The metric system, which was an attempt to bring order to all of these various different measurements, happened much later in France after the French Revolution.(25 votes)
- Is there any way to remember this chart better? I mean, Sal did a great job but I still find it confusing.(5 votes)
- we don't use gallons, ounces, pounds, pints and quarts in Australia! How am I meant to learn this?(6 votes)
- Learn how to convert gallons, ounces, pounds, pints, and quarts to your Australian metric systems.(7 votes)
- How do you know if a spoon is a teaspoon or table spoon?(7 votes)
- a spoon is probebly 2 teaspoons(4 votes)
- Is their a greater amount than gallons?(6 votes)
- yes, there is such thing as 2 gallons:)(4 votes)
- up vote me i up vote you(6 votes)
Let's do a survey about how we would measure the volume of fluids under US customary units. So the smallest volume of fluid that you'll hear people talk about-- and this will often be in cooking recipes or something like this-- you'll talk about a teaspoon. And most of us have teaspoons that are roughly the size of a teaspoon in our cupboards someplace. So this recipe might call for a teaspoon of sugar, or a teaspoon of salt, or a teaspoon of oil. And you've seen what it looks like. But those are the smaller spoons that you might have in your cabinets in your kitchen at home. So this might be a teaspoon right over here. Now, if you were to take 3 teaspoons together, you have something else that you would probably have in your cabinets. So if we multiply this volume, so let's say this right over here is a teaspoon. This right over here is a teaspoon of some substance. If you multiply that by 3, then you get to the tablespoon. So 3 teaspoons equal 1 tablespoon. So a tablespoon's going to be a little bit bigger. So a tablespoon might look like this. These tend to be about the size of the larger spoons that you have in your cupboard, so a tablespoon, just like that. So if you have 3 times the fluid, you get to a tablespoon. Now, if you take 2 tablespoons, put them together, then you get to the ounce. And I have to be careful here. You get to the fluid ounce. And the US customary units, they aren't designed to be super, super clear. Because you also have the ounce as a measure of weight. You have the ounce that is a measure of weight, which is equal to 1/16 of a pound. And now you have a fluid ounce, which you could either view as 2 tablespoons or, as we'll see, 1/8 of a cup. Now, you might say, well, why are they both called ounces? What's the relationship between the two? Well, there is somewhat of a relationship between the two. If you took a little bit over an ounce of water, so a weight of ounce of water, slightly over an ounce of water, that volume is going to be about a fluid ounce. An ounce of water in weight and a fluid ounce of water in volume are very, very, very close, although they aren't exactly the same thing. Now, if you think about, what would you measure here? We already talked about recipes, and teaspoon, tablespoon, fluid ounce. You might be thinking about how much medicine maybe someone might take. Maybe they need to take 2 tablespoons, which would be equivalent to a fluid ounce. Now, if you take 8 fluid ounces and put them together-- so let me draw a fluid ounce here just so we still have drawings. So you could imagine some medicines have a little cap on the top that you could put the medicine in. So if you do 2 tablespoons in it, maybe that will be a fluid ounce. Now, if you take 8 fluid ounces then you get to a cup. And many of us have this in our kitchens. We have a measuring cup that will measure exactly a cup. And you might have a recipe for pancakes that say, hey, put a cup of flour in there. And also a lot of the cups that you have in your house might be around might be around the size of a cup. If you look at, say, a can of soda that you're probably familiar with, a can of soda, the typical can of soda, is 12 ounces, not 8 ounces. So a typical can of soda is a cup and a half. We see that a cup is 8 fluid ounces. A typical can of soda is 12 fluid ounces. So it is equivalent to a cup and a half. Let me make sure this looks like a can of some kind. So if this was 12 ounces, this is 1 and 1/2 cups. But it gets you a sense of how much fluid volume a cup actually is. Now, if we were to take 2 cups, now you're dealing with a pint. And so you might have seen pints. Sometimes they're in these small cartons. So a pint might look something like this in a carton. That looks more like a house. But I think, hopefully, you get the picture that this is intended to be a carton of some kind. So you have something like that. And so the pint, it's 2 cups. And so let's say this is the fluid inside of it. Let's say this was transparent, and you might see it there. Or if you have a very large mug, that might be the size of a pint, so if you have a very large mug like this. So my best attempt at drawing a large mug, this might be roughly equal to a pint. So let me put some fluid in here. So there you go. There's my large mug. It's got a pint. Now, if you take 2 pints, now you are dealing with a quart. And you might have found yourself going to your local convenience store and buying a quart of milk. A quart of milk, those are kind of those longer but still kind of skinny looking-- so it might look something like this. I'm trying to draw a carton of a quart of milk. And then finally, if you were to take 4 quarts together, you get to a gallon. So you take 4 quarts together-- so times 4-- you get to a gallon. So we're most familiar with a gallon of milk. So let me see if I can draw a gallon of milk here, my best attempt. Well, I'm sure someone could draw a better gallon of milk here. But at least in the US, it tends to be one of the most typical ways that they sell milk. And it has, oftentimes, a little red or orange thing right on top there, so a gallon of milk. So just to review things, right here, I just multiplied from the smaller unit to the larger one. But if you want to think about everything in terms of ounces, that's one way to think about it. A cup right over here is equal to 8 ounces. 8 ounces is equal to a cup. If you multiply that by 2, then you get to 16 ounces is equal to a pint. If you multiply that by 2, you get 32 ounces. 32 ounces is equal to a quart. And if you multiply that times 4, you get 30 times 4 is 120, plus 8. You get 128 ounces per gallon. And so next time you go buy something in the supermarket, I encourage you to look at how it's being measured. And you'll see that oftentimes you might buy a quart of milk, but they'll also say that this is a 32-ounce container. And in this context, they're talking about fluid ounces.