Videos

Measurements: Measuring Liquid Volume with a Graduated Cylinder

Added Aug 18, 2015 •

Copy this URL:
Embed code:	<iframe class="edlio-embed-player" type="text/html" width="640" height="360" src="//bhs.bartlettschools.org/apps/embed/?v=85149" frameborder="0" allowfullscreen></iframe> Change dimensions

Show Transcript

okay now we're going to talk about finding volume or measuring volume and to find volume will use you waited cylinders which of these tall looking containers here okay you may notice that a beaker has volume marks on it but it's terribly inaccurate so to order to find volume correctly we need to use a graduated cylinder okay alright so the really important thing to know about finding volume in a graduated cylinder came when water is poured into a graduated cylinder it forms was called a meniscus in other words and see how in his picture here I've shown that water kind of Curves up the edges right if you measure at the top of the curve that is not an accurate measurement you must measure at the bottom of the curve or the bottom of the Menace thanks water kind of sticks to the edges and forms a little curve and we'll look at that in just see if you're using a glass graduated cylinder notice it has yellow piece of plastic at the top of it did that's not to use to measure that actually protects it if it falls over you keeps it from breaking okay so that needs to stay at the top always stay at the top okay till this practice measuring now so let's say you have an of water and you pour it into the graduated cylinder now how much water do we have K first thing  never look at it from up here  okay if you're going to measure using a graduated cylinder you always need to get down I level the water or whatever liquid your measuring okay and then once I get close to it here you can see the meniscus you see how the liquid curves up the sides okay measuring at the top of the meniscus you need to measure at the bottom of them in this okay let's see how much water we have in here it's colored water okay notice right here the big line is 70 m l k noticeable over there is 60 there's 10 marks in between 1 2 3 4 5 2 5 longer would 6 7 8 9 and 10 70 okay so that means each Mark is 1 ml right count starting at 70 right 1 2 3 4 5 so that 75 okay the top of the new when is this is actually at 76 but we always read the bottom of the meniscus so this is 75 mL of water tank if you're from up here you might get a wrong measurement if you look from down here again you might get a wrong measurement cuz that looks more like 76 exactly and I level it to do if I want a little bit more let's say I want 77mm instead of 75 okay can you use a pipette which is an fancy word for dropper okay so I've gotten some more liquid in my dropper and my pipette and I'm going to hold it over here above  how the in the graduated cylinder and then I need to look as I'm dropping drops in to see think it's up to the appropriate place alright remember we want to look at the bottom of the meniscus only not the top okay so now I'm going to add drops with my dropper with my pipe it  and I keep dropping it in okay now I'm up to notice the bottom of the meniscus now is at 76 the top is at 7 7 so I need a little bit more so I keep dropping  until the bottom of mine in meniscus now is at 77 so that's how you add water okay are added liquid to to bring it up to the correct measurement alright so if you need to remove some water or liquid way to do it is to dump some of it out and then fill back up with the pipe that again okay if you try to stick the pipe it down in there to take some when you put the type it in it actually changes the measurement just a little bit so it's best just to dump it out and then fill it back up with the pipe

Uploaded by Laura Houston.

Videos

Measurements: Measuring Liquid Volume with a Graduated Cylinder

More videos from Laura Houston