The bees have drunk a
bit more than a gallon of sugar water in
the last couple of weeks. By my estimate, that
should have filled about a third of a Warre hive box up with honey, but
the view from below is exactly the same as it was when I started my
force-feeding campaign.
Chances are the bees are
simply filling in the upper boxes, which is why I don't see any capped
honey below. I wish I could be sure, which brings me to a
physics/math question for my geekier readers.
Some people weigh a hive
by tipping up one side and putting a bathroom scale underneath, then
tipping up the opposite side and repeating. I believe they
usually just add those two figures to come up with a total weight for
the hive. But I'm not sure that makes sense, and I feel like the
angle would also be important. If you don't know if the honey is
evenly distributed throughout the hive, can you gauge the weight of a
hive piecemeal?
My first thought is that the angle definitely matters. I'm not relying on my great physics knowledge (that I don't have)but on the fact that if you do a pushup on a raised surface, your arms are doing less work (meaning more weight on your feet/on the scale at the other end) than if you were flat on the floor.
How much less, I couldn't say for sure. Related to my analogy (and since I don't want to look up physics equations), "a standard pushup (hands and feet on the floor with your core tight) uses about 65 percent of your bodyweight. Incline pushups, in which the hands are higher than the feet such as doing a pushup with your hands on a bench, uses about 50 percent of your bodyweight."
Read more: http://www.livestrong.com/article/444004-how-much-of-your-body-weight-do-you-lift-in-a-pushup/#ixzz2A2CCX5Mc"
So in theory, it would be about 50/50 on each side depending on your angle but how do you make sure you're not getting an extra 2% or so, and would that make a serious difference when trying to figure out how much honey is in the hive? Seems like it wouldn't be accurate enough.
Tipping the hive moves the center of gravity of the hive, and will mess up the result a little bit unless you either keep the hive level or correct for it in your calculations. But unless the hive is very tall and narrow, I don't think the deviation will be very big.
But accurate readings can be easily had by hoisting the hive up using a long lever and a known mass as a balance scale, or by making a board that sits on the scale and allows you to place the whole hive on the scale without obscuring the dial. But lifting the hive might be a two person job if you are not using a lever.
One langstroth deep holds about 7 lbs of honey. It takes about 6 lbs of sugar to make 7 lbs of honey. Two cups of sugar is one pound. So that's 12 cups of sugar to fill one deep frame...How many cups of sugar were in your gallon of syrup? Not sure what your frame is, but a gallon of syrup doesn't make that much "honey".
Anonymous --- We have them on fall sugar water, which is much richer than sugar water people often use in spring. My recipe is 3.5 cups of sugar plus 2 cups of water to make one quart. So, a gallon would be 14 cups of sugar, or about 7 pounds of sugar. Since this is a Warre hive, with one full box containing only about 26 pounds of honey, that should fill up about a quarter of a box.
(I'm also enjoying everyone else's thoughts on the weighing question. Lots to ponder....)
Just few more pennies on the pile...
(1) If you have two scales and can set the hive on them such that it is only supported by the scales (not touching the ground), it doesn't matter what the angle is (within reason!) -- the total of the two scales is the total weight of everything supported. (Hive, frames, quilt, bees, comb, honey, etc.) For even more stability, you might want a third scale. Or a fourth, or more. You'll still take the total of all the scales, and that's your total weight.
(Actually, if you had a way to weatherproof the scales, you could leave them in place all year long and watch the weight fluctuate throughout the seasons... Sounds like fun, right?)
(2) If you make shims for the corners that are the same height as your scale, you can keep the shims there "permanently" and when you want to weigh, place the scale under one side, remove the shims from that side, record the weight, replace the shims, and repeat for the other side.
(3) As Roland says, if you don't have the hive level, the c.g. is going to shift, which changes the percentage of the weight that lands on the scale for each measurement. Assuming that you're starting with a level hive and the scale is lifting one side higher, you'll be tilting the c.g. away from the scale, so the weight you see will be slightly lower than if the hive were level. Overall, then, this method will give you a recorded weight that is lower than the actual weight. If all you're worried about is, "Do my bees have at least enough food to overwinter?" then this method is safe. A bit inaccurate, but in a safe way.
Since as soon as 2 corners are off, you have lifted enough, it doesn't make too much difference in the center of gravity: You only need to lift the front or the back 1/4 to 1/2 at most. A way to cut down on the error in the measurement is this: Since you have hopefully installed your hive with a slight frontward tilt for water rain off (High in the back) lift the front only until the hive is absolutely level. Then you will not have any error. Since you multiply the error by 2 to get the whole weight, you may want to go that route. I have a slit at the back where I can insert a pry scale, so I will continue that way, even if it creates a small error. Also, if you weigh your hive often and consistently the same way it will give you a very accurate picture of the health of your hive. The bees build their hive from the bottom up and the inside out, so the honey, inside the stack of frames has the general shape of a cone. In view of that, tilting the whole stack by 1/2" will not give you a huge error: the center of gravity for that mass is roughly at the center of the bottom hive box