[Diy_efi] OT - Measuring less than an ounce

[Daniel Nicoson]

Everyone, thank you for all the suggestions.  Sunday we did the balance
method in our basement with a home brewed balance beam.  My daughter was a
little pissy at first but once we started "making stuff" she 'got it' and
made some good suggestions actually saving us some time.

The resulting small quantity was VERY few grains of this fertilizer.  Should
be interesting.

Thanks,

Dan Nicoson

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Andrew Hopton
Sent: Monday, January 15, 2007 1:36 PM
To: diy_efi at diy-efi.org
Subject: RE: [Diy_efi] OT - Measuring less than an ounce

I know this is bit belated, and I see you've already had some good
advice - here's my 5c worth - Try talking to her science teacher -
he/she should have already had/solved this issue.  At the very least,
the school should have a Metzler balance (or similar) in the Chem lab
which should be accurate to .01 gram (maybe better) (1 ounce = 28.35
grams IIRC, so .0213 oz = .604g)

Cheers.

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]
On Behalf Of Daniel Nicoson
Sent: Friday, 12 January 2007 1:54 PM
To: DIY_ EFI
Subject: [Diy_efi] OT - Measuring less than an ounce


I hope you guys don't mind this totally Off Topic, but you are one of my
more scientific group of friends.

I need somebody to review my physics/methodology below:

Helping my daughter (16 yr old) with a science project.  She is testing
two types of fertilizer by growing three equal size patches of grass,
fertilizer A, fertilizer B, Control.

Here's the real problem:  We need to measure VERY small amounts of
granular fertilizer.  The grass patches are only .38 ft^2, one
fertilizer amount comes out to .0213 ounces, the second comes out to .24
ounces.

I don't know about you but I don't have that kind of scale around here.

Here's my idea, please scrutinize, simplify, accurize...

I am going to weigh 300 pennies tomorrow at work on an electronic postal
scale, I think it reads out in 10ths of ounces.  If they read greater
than 1 ounce I should get 2 significant digits, possibly they will weigh
more than 10 ounces and we can work with 3 significant digits.  The
assumption is that the pennies all weigh the same.  This will give me an
accurate weight of one penny.

Back home this weekend we will make a simple balance beam.  Since I
don't have jeweled bearings, I'm thinking a simple string at the fulcrum
will give as consistent results as anything.

At the short end, say 10-to-1 ratio of lengths, I will have a hanging
container with pennies.  At the other end I will have a plastic medicine
bottle to hold the fertilizer.

To zero the balance scale out I will add coins (any size) until the
coins balance out the whole apparatus.

Next, I will have to do the math as to how many pennies equal 10 times
the weight of the desired fertilizer weight.  Place this measured amount
of weight in pennies on the short end of the balance.  Next, fill the
medicine bottle with fertilizer until it balances.

Done, measured, accurate weight of fertilizer.

Does all of that make sense?  It does to me.

The hardest part will be helping her learn what we just did so she can
defend her process on the project.

Suggestions are appreciated.

Dan Nicoson


_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
Main WWW page:  http://www.diy-efi.org/diy_efi

_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
Main WWW page:  http://www.diy-efi.org/diy_efi