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Understanding mass (grams and kilograms)

CCSS.Math:

Video transcript

so let's talk about the unit of measurement called the gram and the gram is a unit of measurement for measuring mass now what is mass well you might have seen in everyday language someone might look at a feather let me see if I can draw a good feather so a feather like this and say hey this is not very massive this is not massive and notice you have that word mass in there and then they might point to some big boulder some big heavy Boulder let me draw a big heavy Boulder and say this is massive this is massive and so just with those examples you might get an intuition for what mass is it's how much it's how much stuff there is and it's related to weight and I said related to weight not the same thing as weight because later on when you take physics you will learn that mass and weight are related but they're not exactly the same thing now if you're on a given planet and the same distance from the center of that planet roughly speaking mass and weight will be strongly related to each other something with more mass is going to have more weight to things with the same mass once again if I'm on the same planet at the same distance from the center of the planet they are going to have the same weight so you'll often hear people say how many grams does that thing weigh they really should be saying how many grams does that thing mass but it's okay because as long as we're staying on earth roughly you know at sea level plus or minus a little bit or even if we're a little bit further away from sea level mass and weight it's it's not crazy to hold them a little bit interchangeable and one way to to gauge something's mass is to hold it and if you can and say okay how much does this weigh because the more something weighs the more its mass is going to be the more its mass is going the more something's mass is going to be the more it's going to weigh once again assuming we're on the planet etc etc when you take physics class you'll learn that they are different concepts that are closely related to each other so that's what a gram is now another thing that you we'll see in the context of mass and measuring mass is the kilogram kilo kilogram and all the kilogram is all a kilogram is and you're going to see the prefix kilo over and over again or kilo or kilo over and over again in your in your I guess your education careers especially when you're thinking about units but kilo is just a prefix for a thousand so that literally means one thousand grams so instead of saying two thousand grams I could say two kilograms so with that out of the way let's see if we can get a sense for what one gram or different numbers of grams of masses are and what different numbers what might have a mass of one kilogram or ten kilograms or 100 kilograms and that's exactly why I got all of these pictures prepared so if you want to get a sense of something that has a mass of one one gram think of a paper clip and I have this little squiggly thing here because that right there that means roughly every paper clip isn't going to be exactly 1 gram it might be one and a half gram there might be small paper clips that are half a gram but it gives you the sense of what would have a mass of 1 gram and if you want to know how much something with a mass of 1 gram weighs on the surface of the earth well you could just hold that paper clip and kind of judge on you feel how much it's pulling down on your hand now or how much the the weight of it is pushing down on your hand I guess I could say now if you want to get a sense of things that are a little bit more massive a pencil is five times as massive as a paperclip and hopefully you'll see that if you hold five paper clips in one side and a pencil on the other side you'll see that they roughly have the same mass and they'll be their weight will be roughly the same now a little bit more massive you could think of a field mouse a field mouse is equivalent to the mass of roughly four pencils or 20 paperclips you wanna get even more massive you can think of a kitten so a kitten after a couple of weeks it's still a kitten now it's still not a fully grown cat it'll have a mass of about 200 to 300 grams and this makes this makes rough rough amount of sense you could imagine this thing having the same mass as maybe 10 or 15 of these little field mice you can imagine the mouse the mouse is about it's about that size right over there so that let me see if I can draw it is and knows I'm not do a better job drawing the mouse but that makes that makes some sense so what if we get even larger what if we get into the ranges of say a thousand grams well now we can start talking about kilograms and just as just to be clear when I put a G here that's just an abbreviation for gram so this is 1 gram 5 grams 20 grams and now if you wanna go to a thousand grams you could think of something like a a hardcover a hardcover textbook like this one and there you know obviously some textbooks are huge but the one that I'm showing here I didn't weigh or or figure out the mass of this exact one but it would have a mass of roughly one kilogram or 1000 grams so that's a kilogram right over there a thousand grams a fully grown cat that's about three to five kilograms depending on how fully grown it is or I guess just how big of a cat it is so that's pretty interesting a fully grown cat is more than 10 times the mass more than ten times the mass of a kitten actually that makes sense so I'm most fully grown humans are more than ten times their mass when they were when they were very very young or actually right roughly 10 times the mass of when they were very young so it actually makes it actually makes it actually makes sense now if you want to get even larger you can go to a large ape like a human being particularly this one right over here 70 kilograms and this is actually pretty close to my actual mass 70 kilograms and just you get a sense of what that would mean if you're used to dealing with pounds I weigh about 100 and a little over 160 pounds so that's about 70 kilograms or 1 kilogram is roughly 2.2 pounds if you are used to thinking in terms of pounds but once again pounds are a unit of weight while kilograms are a unit of mass and then if you want to get even heavier you want to get 10 times or I could say 10 times more massive than a human being then a normal sized human being you might get to something like this Clow and this cow would have a mass of 750 kilograms so how many paper clips would you need to have the same mass as this cow well you might be tempted to say 750 but remember this is one gram this is 750 kilograms so the mass of this cow is actually 750 thousand grams so you would need about 750 thousand of these paper clips to have the same mass as this cow