Lost 13kg in less than a week

Ok, I get it. I was not weighing the hives in a sensible way. I will do an experiment later today.

I'll fill a suitcase with bricks (unevenly). I'll weigh when lifting one end half off the ground (a) then do the same at the other end (b), then I'll lift it off the ground completely (c). I'll let you know if a+b = c

ricrdbees is, as usual, on another planet. The only way to be sure of the weight is to sum the two weights - whether back to front or side to side, irrelevant of the frame direction. Half doing it may give an apparent good indication but CANNOT be guaranteed.

Very simple physics as usual (only understood by peope from this planet?). Technically each side should be lifted, but by zero distance. Raising each side excessively will reduce the accuracy of the operation - think here vehicles which transfer all the weight onto one or two wheels; when the weight on the side that is lifted off the road is reduced to zero, the vehicle is likely to topple over, not return to stable equilibrium on the side expected. All to do with the centre of weight (often referred as the centre of gravity) moving outside the base. Try it with any box on a flat surface and you may get the idea, if you don't already understand.

BeeBeeKa said:

The Best hive of my bees brining in from 0.75 to1.75 kilo of nectar a day now, depending on weather. Mostly - Iwy, but a little bit of heather also. I weighing only honey super(which is a Langstroth Brood box in fact) in a middle of a day, for a fun also , and do not see any weight reduction for this obvious reasone . It was only a 2 brood frame nuke( and 2 stores) I`ve got on 30.06.14, so I`m pretty happy having a chance to get any honey this year.Top BB weighs over 20 kilo already…in the middle of the day as I sayed
Robbing bees move Zig-zag way at an entrance afaik, so I woud not worry much about it If I do not see this attribute.

Click to expand...

I have a pint of what he has been drinking please...

Now I have a picture in my head of a hive teetering precariously at 45degrees!

I have found a difference of up to 3kg between the sides of a hive.

Example 15 + 18 = 33kg

By only weighing one side and doubling you would get readings of 30 or 36kg; which is a significant difference.

JohnyP said:

Ok, I get it. I was not weighing the hives in a sensible way. I will do an experiment later today.

I'll fill a suitcase with bricks (unevenly). I'll weigh when lifting one end half off the ground (a) then do the same at the other end (b), then I'll lift it off the ground completely (c). I'll let you know if a+b = c

Click to expand...

If they still did 'O' level Physics you would already have done that experiment!

Davelin said:

Now I have a picture in my head of a hive teetering precariously at 45degrees!

I have found a difference of up to 3kg between the sides of a hive.

Example 15 + 18 = 33kg

By only weighing one side and doubling you would get readings of 30 or 36kg; which is a significant difference.

Click to expand...

Indeed, a couple of years ago I tried weighing a hive through the winter. On the left the weight fell steadily for a couple of months, the right staying steady. Then the left fell rapidly, and the right increased before a slow fall. Best guess is that the cluster started to the left, then moved right. It wasn't quite as clear at the time as a two line summary after the event but it does show doubling either side would have been misleading.

Hi all,
It is wrong to assume that the brood nest ends up in the middle of frames come autumn/winter. Winter preparations in this respect started early on my hives. Some concluded previously on the forum that this was due to the heat around the cluster was retained better by being closer to the wall on one side?

A further inaccuracy comes from the upper suspension point (YOU) is a flexible compressable structure that is always making small movements. You might think your arm is still but it isnt.
This now makes the averaging of the results critcal, this is either the sw of the device or you. check it out by taking at least 5 measurements , look at how far the measurements are spread.

whether it is usable or not depends on your purpose. A spread of 4kg might be close enough when you are working with a 10kg safety margin in stores.

Davelin said:

If they still did 'O' level Physics you would already have done that experiment!

Click to expand...

but alas the analysis of the errors e.g. standard deviation is only just coming into A level physics.

This was a complete pain in the gluteus maximus (j lo is famous for her's ) before affordable pocket calculators did the whole job..

Luckily these arrived in the nick of time during my first term

there is also the fact that we're not so much concerned about the absolute total weight of the hive, but the change in weight over time.

So whichever method of weighing you use, as long as you do it consistently, you will be able to determine if the hive is gaining or losing weight.
Given a visual estimation of the weight of stores at the start of winter, the differences will then will give an estimate of the amount remaining as the weight drops over the winter.

itma said:

I think you are missing the point that hive weighing (or hefting) becomes important, possibly critical even, at the end of winter.
Long before then, one needs to get a 'feel' for what stores are inside - but, that training apart, through the rest of the year, the weight may be interesting, but its not important to get it right.

For winter 'hefting' (or weighing), one can be mislead if, as you specifically posted to recommend, one only hefts (or weighs) one side of the hive.
For the times it really matters, that's bad advice.
Which is why I posted. Not pedantry.

Click to expand...

derekm said:

but alas the analysis of the errors e.g. standard deviation is only just coming into A level physics.

This was a complete pain in the gluteus maximus (j lo is famous for her's ) before affordable pocket calculators did the whole job..

Luckily these arrived in the nick of time during my first term

Click to expand...

Blimey Derekm, your a bit serious at times. You need a hobby.

Why does everyone get so uptight? Surely this is supposed to be a forum to exchange advice and opinion on beekeeping....

Maybe I've got neat and tidy bees but since changing to aligning the frames parallel to the entrance I've never found more than 2lbs difference between either side so stopped bothering.

When they were aligned 'fore and aft' there was a huge difference between the weight of either side......the (lighter) brood tended to be on the S side.

I still 'heft' from the back - but that's just noticing the change from last time.

derekm said:

ivy nectar is only about 11% sugar .

Click to expand...

Derek: you keep saying that but LASI reckons it's 49%. I haven't done the thermodynamics, but 11% syrup must be pretty marginal. http://www.sussex.ac.uk/broadcast/read/19003

<ADD>"Back of an envelope". Water evaporation, 2260 kJ kg-1 approx. Sugar calorific value 4 * 4200 kj kg-1.

11 kg sugar 89 kg water goes to 11kg sugar 2 kg water so positive balance 11*4*4200 - 87*2260 kj = -11,820 kj for 100kg of nectar. Ivy needs to up its game or not attract the bees, it would appear, and it has. At 49% and 100kg of nectar we get 49*4*4200 - 42*2260 kj = 728,280 kj and ivy is not extinct. Hurrah!</ADD>

TryingToLetThemBee said:

Derek: you keep saying that but LASI reckons it's 49%. I haven't done the thermodynamics, but 11% syrup must be pretty marginal. http://www.sussex.ac.uk/broadcast/read/19003

<ADD>"Back of an envelope". Water evaporation, 2260 kJ kg-1 approx. Sugar calorific value 4 * 4200 kj kg-1.

11 kg sugar 89 kg water goes to 11kg sugar 2 kg water so positive balance 11*4*4200 - 87*2260 kj = -11,820 kj for 100kg of nectar. Ivy needs to up its game or not attract the bees, it would appear, and it has. At 49% and 100kg of nectar we get 49*4*4200 - 42*2260 kj = 728,280 kj and ivy is not extinct. Hurrah!</ADD>

Click to expand...

I was using some earlier research, which covered a range of flowers GR WYKES 1952.. http://www-02.all-portland.net/bj/053/0294/0530294.pdf
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1952.tb06127.x/pdf
Thank you for pointing out the new stuff, ive got some slides to change by a week on tuesday then
from the paper you mention:

The total sugar concentration in ivy nectar recorded in this study was 49.3% (w/w), which is considerably higher than that reported previously in Italy, 3.5–7.5% (Vezzaet al., 2006) and Britain, 10-11% (Wykes,1953) (values reported in different units converted to %w/w as recommended by Bolten et al.(1979)). The difference observed between our data and previous studies may be caused by both nectar being diluted by other water sources, such as dew and rain, and being concentrated by evaporation, which is facilitated by the open structure of flowers, where the nectar is secreted on the exposed surface of the floral disc.

full paper here

@ Derek, you may be interested in this one too http://www.acta.media.pl/pl/full/7/2014/000070201400013000030010900122.pdf

oliver90owner said:

Very simple physics as usual (only understood by peope from this planet?).

Click to expand...

oliver90owner said:

Technically each side should be lifted, but by zero distance. Raising each side excessively will reduce the accuracy of the operation

Click to expand...

And the closer to the center of the hive your strap is( if you use them), the heavier weight of side you`ll get as the gear gets shorter.

TryingToLetThemBee said:

....

<ADD>"Back of an envelope". Water evaporation, 2260 kJ kg-1 approx. Sugar calorific value 4 * 4200 kj kg-1.

11 kg sugar 89 kg water goes to 11kg sugar 2 kg water so positive balance 11*4*4200 - 87*2260 kj = -11,820 kj for 100kg of nectar. Ivy needs to up its game or not attract the bees, it would appear, and it has. At 49% and 100kg of nectar we get 49*4*4200 - 42*2260 kj = 728,280 kj and ivy is not extinct. Hurrah!</ADD>

Click to expand...

Your back of the envelope assumes the energy to ripen comes out the nectar ripened...
They dont need to fuel ripening bees on honey, they can be fuelled with extra nectar...

I've a both sides of an a4 envelope analysis, and its not as bad as you think, but definitely is still a hard task for small reward at 11%

BeeJoyful said:

@ Derek, you may be interested in this one too http://www.acta.media.pl/pl/full/7/2014/000070201400013000030010900122.pdf

Ivy nectar is composed mainly of glucose but also contains sucrose and fructose [Vezza et al. 2006]. The sugar content fluctuates within a wide range (25–81%) and depends on relative air humidity and the phase of nectary avtivity [[Koltowski 2008].​

Click to expand...

This why I prefer Physics/Engineering where you can take 250 measurements of temperatures in 45 minute and get a standard devation (spread) of less than 0.1%. Start fiddling with biology and you get this "fluctuates within a wide range " and it takes weeks to years to collect the data.

P.S. The original source is written in Polish (Koltowski) so i'll stick with the one from Brighton

the closer to the center of the hive your strap is( if you use them), the heavier weight of side you`ll get as the gear gets shorter.

I think that may need some further explanation. There is only one sensible place to lift if it is the side and not the middle - the side? Or perhaps it is different up Uranus way? I don't personally expect the weight to decrease by using a 'shorter gear' - a shorter strap attached to the lifting point would presumably have less mass than a longer one? Anyway a hook on the side is usually a good enough place to use as a lifting point. You do realise, of course, that the gravitational field strength will be differentbon your planet?