# What the heck is my buddy talking about?

## Main Question or Discussion Point

Today in chemistry, the professor made a typo that led to some entertaining results.

"Use dimensional analysis to convert 25 in2 to liters."

We were asked to convert square inches to liters. I thought jokingly "man this class is hard!"

I later informed my friend of the humorous question. He said that it wouldn't be useful, but that it could be done (??) and that any unit can be converted to any other. I agree with that, but only within the same property we are measuring..

"It's not useful like cubic inches but I'm sure it could be done."

Were his words. I expressed my lack of understanding, and said that it makes about as much sense to me as converting kelvins to feet.

He said that it wouldn't be useful, but it could be found. For example liters could be "kelvin-ohm-candela-in2/newtons" (completely made up example) and that you could find the square inch value if needed.

Soo...

What the HECK is he talking about?

He's a very, very intelligent person but I have no idea what he's talking about. Can someone clarify?

As far as I'm concerned if I tell someone to convert 2 square inches to mL, it makes about as much sense as asking someone to convert a cow into blue radians, divided by horseshoes.

Yeah, I don't see how that makes sense, except in this way. You could think of it as "How many liters of liquid can I put in any 2D surface?" which would be 0L.

So I guess you could say 25 in^2 = 0L, in a way. Perhaps pointless, but true in a sense.

symbolipoint
Homework Helper
Gold Member
What was the application? [STRIKE]How would the volume depend on area? Conversion depends on the application.[/STRIKE]

OK, I misread. The teacher made a typographic error. If there were not a typing mistake, one would need to know the specific application.

symbolipoint
Homework Helper
Gold Member
Here's another idea.

An absobant material can take in a specified amount of volume of a liquid per specified unit of absorbant area. Some quantity of liquid is spilled. How much length of absorbant sheet is needed to soak up the spill? The width of the absorbant sheeting also needs to be used.

Here's another idea.

An absobant material can take in a specified amount of volume of a liquid per specified unit of absorbant area. Some quantity of liquid is spilled. How much length of absorbant sheet is needed to soak up the spill? The width of the absorbant sheeting also needs to be used.
No.

Converting units and using a given amount of a unit to find a completely different unit aren't the same.

No amount of area equals an amount of volume. They can correspond to one another in some way, but that doesn't make it a conversion.

You cannot convert between different dimensions or different entities of measure, end of story.

An absobant material can take in a specified amount of volume of a liquid per specified unit of absorbant area. Some quantity of liquid is spilled. How much length of absorbant sheet is needed to soak up the spill? The width of the absorbant sheeting also needs to be used.
You're talking about a mathematical relationship or equivalence, not converting different units of measure.

Last edited:
Compared to what? A mouse with an extra chromosome?

You cannot convert between different dimensions or different entities of measure, end of story.
Okay. I appreciate the info but there is no need to insult.

symbolipoint
Homework Helper
Gold Member
Topher925 and 1MileCrash,
You ignored what I wrote. Read again. I know the difference between unit conversion and a correspondence between different dimensioned measurements. In fact, so do you, and you will likely find and use them in the real world.

While I later recognized the mention of a typographical error, a good response was also possible for:

What the HECK is he talking about?

He's a very, very intelligent person but I have no idea what he's talking about. Can someone clarify?

Today in chemistry, the professor made a typo that led to some entertaining results.

"Use dimensional analysis to convert 25 in2 to liters."

We were asked to convert square inches to liters. I thought jokingly "man this class is hard!"

I later informed my friend of the humorous question. He said that it wouldn't be useful, but that it could be done (??) and that any unit can be converted to any other. I agree with that, but only within the same property we are measuring..

"It's not useful like cubic inches but I'm sure it could be done."

Were his words. I expressed my lack of understanding, and said that it makes about as much sense to me as converting kelvins to feet.

He said that it wouldn't be useful, but it could be found. For example liters could be "kelvin-ohm-candela-in2/newtons" (completely made up example) and that you could find the square inch value if needed.

Soo...

What the HECK is he talking about?

He's a very, very intelligent person but I have no idea what he's talking about. Can someone clarify?

As far as I'm concerned if I tell someone to convert 2 square inches to mL, it makes about as much sense as asking someone to convert a cow into blue radians, divided by horseshoes.
Were there circumstances that preceded the assignment - perhaps in the context of the properties of a specific liquid discussed that you haven't posted?

chemisttree
Homework Helper
Gold Member
I expressed my lack of understanding, and said that it makes about as much sense to me as converting kelvins to feet.
You are smarter than your very, very intelligent friend.

He's a very, very intelligent person but I have no idea what he's talking about.
If you two were alone when he said that, and for your friend's sake I hope so, that makes two of you.