Graduated cylinder a 10 or 25 ml graduated cylinder...

Graduated cylinder - A 10 or 25 mL graduated cylinder dispenses the volume you are reading from it to about $\pm$ 0.1 mL. 100 mL graduated cylinder has an error closer to $\pm$ 0.5 mL so you MUST read graduated cylinders to ONE decimal place. Again, please remember that the volume you are reading is the volume the cylinder will pour out (dispense) to another container, not the exact volume of liquid inside the cylinder itself. Liquid stays behind coating the cylinder. 7) Volume = _______ mL Buret - The photo is a buret which also dispenses a liquid. The buret has a smaller internal diameter and can dispense volumes to $\pm$ 0.02 mL, so you MUST read the volume to the SECOND decimal place. Two people reading this buret should each be able to read a volume that differs by no more than 0.02 mL. Pay attention to the buret scale when reading the volume. Note that it is inverted, as compared to that of the graduated cylinder. 8) Volume= _______ mL

Transcript

00:01 Okay.

00:02 All that they're saying is that if we take something like this first example that goes from 20 to 30 and that the marks are every one mill, right? this is 21, 22, 23, 24, right? that we take the difference between the smallest two marks, right? say 26 and 25.

00:31 25.

00:34 And we divide that by five, and that tells us, whatever digit we get there, that tells us the final digit that we should report.

00:41 So in this case, we would get 0 .2, right? so we need to report a number that ends in the 10th place.

00:52 So let's draw the meniscus that we're measuring basically stops right there.

01:03 Okay.

01:04 So then we look at this, and we mentally split the nearest markings up into fifths.

01:15 And we decide which of those fifths it's closest to.

01:18 To me, it looks like it's right on the line, right? it's right on 25.

01:23 That's the nearest fifth, if you will.

01:27 Right.

01:27 So we just say 25 .0, right? and now we've ended at the same correct digit that we got when we took the nearest markings and divided it by 5.

01:36 So 25 .0 mils is how you would report from this one.

01:40 Let's look at a second one that might be a little more interesting.

01:43 Now, we're looking at 3 and 4, and so the markings are actually in 0 .1, right? right, so for example, we take any two markings, doesn't matter.

02:05 This is 3 .3, and the one above it is 3 .4.

02:12 So we do 3 .4 minus 3 .3.

02:15 We divide it by 5.

02:17 We get 0 .02.

02:20 So our measurement needs to end in the hundredth place.

02:26 We do that same thing every time we take the two nearest markings, subtract them, divide by five, and that tells us the place that we need our answer to end in.

02:38 So we're going to answer to the hundredth of a milliliter.

02:42 Let's draw in our meniscus here.

02:54 Okay.

02:54 And the other thing we do is we just need to estimate, you know, we need to mentally take this little block right here and split it up into fifths.

03:04 And then determine which one it's closest to.

03:07 To me, it looks like it's closest to the second fifth.

03:11 That is, it's, if this is 3 .7, let's see, for example, this looks like it's two fifths below that or 0 .04 below that.

03:33 Which tells me that this is 36 .6.

03:37 Oh, sorry...

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