Math Is Fun Forum

SuperLynx

Member

Registered: 2009-06-28

Posts: 335

Volume Precision ?

Would you say the volume of an object are precise measurements of an object ?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,134

Re: Volume Precision ?

hi SuperLynx

There's no such thing as 'absolute' precision so what makes precise measurements will depend on the context.  For example, if you are making a tank to hold one gallon and the finished tank only holds 0.9 gallons, then the measurement wasn't precise enough in the making.

If you're trying to land an unmanned spacecraft on a comet, then the volume of the spacecraft isn't as important as measuring exactly where the comet will be and making small adjustments to the position of the craft.

Sometimes you know the length, width and height of something but would still have a lot of trouble getting the volume.  eg.  You are going to cut down a tree and transport the timber away.  You want to know the weight of wood so you can organise what size truck(s) to use.

So I don't think there is a single answer to your question.  It all depends on context.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

SuperLynx

Member

Registered: 2009-06-28

Posts: 335

Re: Volume Precision ?

The volume of an object in my definition is the volume of a lamp, the volume of a stove, fridge, hair dryer.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,134

Re: Volume Precision ?

hi SuperLynx

I don't think you could get the volume of any of those with any precision.

eg.  For a hair dryer, do you want to count the air inside the dryer or just the solid part. 

One way to get the volume of an irregular solid is to immerse it in a container that has graduation marks so you can see how much the level of water goes up. I do NOT recommend you do this for any electrical item! Even with an object that can be safely immersed, the meniscus (http://en.wikipedia.org/wiki/Meniscus will lead to errors in measurement.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

SuperLynx

Member

Registered: 2009-06-28

Posts: 335

Re: Volume Precision ?

If someone asks you, what is the dimensions of the hair dryer, you could tell them the height and the width of the part you hold; you could then measure the height and width of the part in which the air comes out, then again, you could just tell them the volume in which the hair dryer occupies.  No the handle is not, suppose 5.2" but the part in which the air is released, is 5.2".