Those bundle weren't manipulated. I received them from the Bank of Canada in a sealed (or striped) package.
They have always been keep at a normal temperature.
Note: In the same brick (10 bundles) it may have a difference of 3 grams between bundles.
APP -- 122 grams
HPM -- 108 grams
HPK -- 114 grams
HPA -- 115 grams
HPU -- 110 grams
HPT -- 111 grams
HPM -- 109 grams
HPS -- 113 grams
HAG -- 107 grams
Thank you very much for sharing. Not sure if you had some reason to make these measurements and also to share them but given that I have not seen anyone else sharing this before it is an interesting addition to the general knowledge about the bank notes
There are many interesting observations that can be made about the information you have provided. Here are my two cents worth on the weight issues.
You have listed two HPM prefixes and I believe one of them should be HPN as shown in your pictures. Not a big deal there.
The variations within the CBN prefixes range from 107 gms to 115 gms. That is about 8 grams compared to your variation within a brick of 3 grams. The simple mean of CBN notes is 111 gms (rounded).
The BABN prefix is at 122 grams. This difference appears to be statistically significant and can perhaps be explained by the fact that APP prefix has full varnish compared to all the CBN prefixes which have partial varnish.
How do you explain the wide variation within the CBN prefix?
Were the weights taken with the straps or without the straps? The picture shows that there are different types of straps and if the weights were taken with the straps then it is possible that some of the variations could be a result of the strap. It should be noted that even for the same types of straps the amount of length in the strap can vary and the amount of glue in the strap can vary so even for the "same looking strap" there could be significant variation. I think this might be the major contributor of the variation
As a way of comparison the Bank of Canada in one of its studies has indicated that a bundle of $20 journey notes without the strap weighs 102 grams.
The following other reasons could cause the variations - variation in amount of ink, variation in amount of varnish, variation in amount of paper weight and variation in size. The variation of the lowest and highest weights around the mean are: 4 gms in 111 gms or 3.6%.
A 3.6% variation in length would mean that the note would have to be long or short by 5.5 mm or approximately 1/4 inch. This does not appear to be the case. So variation in size could not explain such a large variation in weight.
One other thing that can cause variation is the moisture content. However if all these notes are maintained at the same temperature and relative humidity then their moisture content variation should be minimal (except for the fully varnished note).
Given all of the above I would venture to make the following conclusions:
The weight difference between CBN and BABN prefix is a result of the full varnish in the case of BABN.
The weight difference between the CBN prefixes is most likely because of the strap. If however the weight presented are without the strap then it would seem that for such a large difference of 3.6% around the mean it would have to be either the amount of ink or the variation in the weight of the paper. However unlike the difference between the CBN and the BABN prefix I do not believe the variations are significant enough to indicate some purposeful change in any of the underlying materials used in the note making.
Separately I will share thoughts on the other observations.