measuring shark teeth and other fossils

[jpc]

A little while ago I complained about people measuring fossils to the nearest 1000th of an inch.  A practice that is absolutely ridiculous.  A thousandth of an inch is about the width of a human hair.  (Probably white person human hair as other races have finer or thicker strands).  If you are measuring forams under the microscope, this is fine.  If you are measuring shark teeth and rex teeth that you can see without a magnifier, this is lunacy.  Anyway, I just saw a post where an Indonseian shark tooth was measured to the nearest hundreth of an inch.  Rather than hijack that thread, allow me to demonstrate my feelings on this.  Here is the photo they shared; 

This measures 6.34 inches.  That what it says on the calipers.  But look at where the top of the caliper is.  It is close to .03 inches off on the tip of the tooth.  So this could be 6.31, or 6.32, or 6.30.  Not sure.  The point is.... that last digit is useless if not just plain wrong.  Thankfully this tooth was not measured to the nearest number of human hairs.  Math people call this concept 'significant figures'.  This tooth is realistically and practically 6.3 inches long.

 

The same happens when my colleague at work translates metric to inches.  "It is 5 cm (=1.9685 inches) long".  No it isn't!!!  It is 1.9 inches.  Did you measure the cm to the nearest ten thousandths?  No, then why did you measure the inches to that fine detail?  Yes, I give him a hard time about it.  And, yes, maybe this is why it irks me on TFF as well.  

 

I urge people to not bother with the smaller units when measuring things this big.  I am sure the sellers measuring these will never see my rant, but thanks for listening.

 

Rant over.  Carry on.

 

 

Edited November 10, 2023 by jpc

[Tidgy's Dad]

11 minutes ago, jpc said:

 (Probably white person human hair as other races have finer or thicker strands).

My turn for a little rant. 

Why is this comment even necessary? The differences would be negligible and not relevant to the point you are trying to make. (and I agree with.)

There is only one human race, the word race to describe different groups of people is an outdated construct that leads to racism.

[DPS Ammonite]

Related matter, why measure a shark tooth on the diagonal; especially when the root may have been added to or repaired? This is a semi rhetorical question since I realize that longer is more money. Can you imagine measuring cars, people, rooms, or buildings on the diagonal?

Edited November 10, 2023 by DPS Ammonite

[FranzBernhard]

53 minutes ago, jpc said:

And, yes, maybe this is why it irks me on TFF as well.  

It irks you, because you are a scientist and know something about significant digits!

Franz Bernhard

[FranzBernhard]

13 minutes ago, DPS Ammonite said:

Can you imagine measuring cars, people, rooms, or buildings on the diagonal?

Lets hope that this habit is not creeping in.

At least, screens are measured diagonally since their invention? Has anyone an explanation for that? First screens were circular, is this the reason?

[North]

1 hour ago, FranzBernhard said:

At least, screens are measured diagonally since their invention? Has anyone an explanation for that? First screens were circular, is this the reason?

I assume it is for consumers. For them it is easier just to see one number to compare. Its ok if there is standard product.

 

1 hour ago, DPS Ammonite said:

Related matter, why measure a shark tooth on the diagonal

For shark teeth it might be because triangular shape with various wideness. Also shape of the roots make straight measuring more difficult. Sometimes crown height is measured straight upwards for more scientific reasons.

[Mark Kmiecik]

3 hours ago, DPS Ammonite said:

Can you imagine measuring cars, people, rooms, or buildings on the diagonal?

 

Can you imagine people maesuring televsion screens, computer monitors, and smartphones on the diagonal?  Each rule has exceptions.

[erose]

4 hours ago, FranzBernhard said:

Lets hope that this habit is not creeping in.

At least, screens are measured diagonally since their invention? Has anyone an explanation for that? First screens were circular, is this the reason?

Screens used to always have the same ratio, 3:4 or about, No longer the case. I used to design exhibits for museums and what I needed was HWD.  Now back to paleo: Shark teeth are measured one way and other critters often each have their own. Looking into the specific morphology of what you are studying is very helpful.

[jpc]

On 11/10/2023 at 7:28 AM, Tidgy's Dad said:

My turn for a little rant. 

Why is this comment even necessary? The differences would be negligible and not relevant to the point you are trying to make. (and I agree with.)

There is only one human race, the word race to describe different groups of people is an outdated construct that leads to racism.

good point, but my reasoning  was that 1) there is variety on human hair so using human hair thickness as a measure is not ideal but at the same time gets the point across, and 2) I imagine that the folks who came up with comparing things to the width of a human hair were probably measuring white people hair.  

 

But your points are valid.  

[Tidgy's Dad]

51 minutes ago, jpc said:

 I imagine that the folks who came up with comparing things to the width of a human hair were probably measuring white people hair.

Yes, perhaps better to compare blonde and dark hair as an example, as they have different widths. (on average)

Edited November 13, 2023 by Tidgy's Dad

[Nimravis]

When I look at a tooth like that, my measurement scale is, “Wow, that is one big tooth”.