Measuring Volume Of An Irregular Shaped Object

Most solid objects, though, are not so simple. So a rock here, and this is a volcanic rock. It's a pretty cool rock. And I found this on the slopes and mountain Vesuvius on the trip to Italy a few years ago. And I'm curious now, what volume is rock out? So how much space this object takes up? So I can't use math to figure that out. And so I need to use a method known as water displacement. So to do that, I need to have the graduate and cylinder. Now, when you get a graduation cylinder, you always want to use a smallest cylinder you can. It's going to be the most precise. However, you don't want to be so small, one of the object gets stuck. So this here is a 1000 mL graduates on there. And the procedure and if you look at the top, it tells you the precision is two 20 mL. What that means is each little line goes up on interval of 20 mL. 

I've already checked in this rock is not going to get stuck. All right, it's not a problem. So this would be a good graduation. So what I'm going to do next is add some water to this graduate cylinder. And I often tell students, you know, do it about halfway, about a third of the way. You don't want two, too much, because then the water overflows easily. And you don't want so little where the object won't fully be submerged. So about a third about halfway. Now, do not try to get an exact number. So oftentimes students will try and get exactly 600 mL or 400, a nice even number. And they basically spend a lot of waste of time, adding a little bit more water, dumping some add in some more. It's not necessary. I just do about half about a third of the life. So let me get some water and we'll do the next step. All right, I'm back with the graduate cylinder. 

As you can tell, it's about third of the Wakefield with water. Now, when you measure the volume of the liquid, you want to make sure that you get down eye level. You read the bottom of that meniscus. So when I look at this now, the meniscus is in between 380 and 400 mL. Going to it's pretty much right in the middle, so I'm going to say it's estimated about 390 mL. So I'm going to break that down. And that's going to be my initial volume of water. Now, need to add the solid object. Now to do this, you want to tilt the graduate cylinder and very gently add the solid objects. You want it to go in very slowly, so no water spills out. Very, very careful. There we go. Now if water does spill out for you, my advice would be to just start over and do it again because if you go through with this, you're going to get an inaccurate measurement and remember you always want to be as accurate and emphasized as possible. 

So as you can tell, the water level has risen. So since The Rock here takes up space, it's going to displace that water and the water level rises. Just like when you go into a bathtub, it was swimming full. So now I'm going to read the volume again. And this time it's right on the line, so it's 500 and 40 mL, 540. So now my, again, my initial volume was 390 mL, final volume was 540 mL. So if I find a difference between those two numbers, how much the volume of water increased, that would be equal to the volume of The Rock. And when I do that, it comes to a 150 millimeters. Now, it would be even better to call the volume a 150 cubic centimeters is typically we use cubic centimeters to solid objects in milliliters for liquids and gases. So using this method, I'll say a 150 mL, a 150 cubic centimeters is the volume of this rock. And this can be used against any sort of solid objects, and no matter how small a helmet. All right, thanks for watching.