Under weight packaging

Ergates

Murphybear said:

Heavens!  I’m sure I did things less complicated than some of this when doing my Physics degree 

Kitchen scales don’t really need to be that accurate.  I use my kitchen scales a lot and have no idea how accurate they are.  My cakes and other bakes never suffered.  

For cooking no.   But if you were about to send a letter to the supermarket accusing them of ripping you off with their chicken livers (for instance) then you might want to confirm your suspicions before doing so.

the_lunatic_is_in_my_head

Ergates said:

It's easier to produce an accurate jug (all molded plastic jugs created from the same press will be the same size) than it is to create and calibrate a set of electronic scales.

That assumes the mold is correct  

Okell

Murphybear said:

Heavens!  I’m sure I did things less complicated than some of this when doing my Physics degree 

Kitchen scales don’t really need to be that accurate.  I use my kitchen scales a lot and have no idea how accurate they are.  My cakes and other bakes never suffered.  

Having known physics graduates among my fellow trainee TS inspectors I think many of them would agree with you!

You were definitely at a disadvantage as a trainee if you didn't have a scientific educational background.  And that was 40 years ago

Okell

the_lunatic_is_in_my_head said:

Ergates said:

It's easier to produce an accurate jug (all molded plastic jugs created from the same press will be the same size) than it is to create and calibrate a set of electronic scales.

That assumes the mold is correct  

True.

I spent a day at a factory in Derbyshire that produced pint and half pint glasses checking the output to make sure the moulds were accurate.

born_again

the_lunatic_is_in_my_head said:

Ergates said:

It's easier to produce an accurate jug (all molded plastic jugs created from the same press will be the same size) than it is to create and calibrate a set of electronic scales.

That assumes the mold is correct  

As well as the temperature is exactly the same for every measurement.

Jaybee_16

After reading through this thread, I checked my cheap kitchen scales. They are spot on up to the 2Kg weights I have here.

Surprised me. 

Okell

If you don't know whether the weights are spot on, how do you know the scales are spot on?

They both might be wrong...

Ergates

born_again said:

the_lunatic_is_in_my_head said:

Ergates said:

It's easier to produce an accurate jug (all molded plastic jugs created from the same press will be the same size) than it is to create and calibrate a set of electronic scales.

That assumes the mold is correct  

As well as the temperature is exactly the same for every measurement.

Not this again.

The difference between 1000ml water at 8C (approx temp it comes out of the tap) and 20C (average room temp) is about 1.5g

If you live somewhere really hot, and the water got up to 30C it would be about 4g. 

So, unless you're carrying out your test in some very strange circumstances, or intentionally using hot water, the differences would be well within acceptable tolerances for kitchen scales.  Certainly able to confirm if the 50g weight difference in a packet of chicken is real or not.

Jaybee_16

Okell said:

If you don't know whether the weights are spot on, how do you know the scales are spot on?

They both might be wrong...

I know the weights are correct as they are Weights & Measures (as it was then) stamped during the time I repaired weighing machines. Been sat in a cupboard since I left the industry. 

Ditzy_Mitzy

the_lunatic_is_in_my_head said:

Ergates said:

It's easier to produce an accurate jug (all molded plastic jugs created from the same press will be the same size) than it is to create and calibrate a set of electronic scales.

That assumes the mold is correct  

Your 'mold' is lonely.  It's missing 'u'.