About how many watermelon seeds are in the average picnic watermelon? Say a 5 pounder.
Is this a contest? Oh, and welcome to the boards, ozzzie.
Careful! it might be a trick question; you can get seedless watermelons now.
Sorry, oz. I’d love to give you a straight answer, but the only sites I’ve seen about the number of seeds are activity idea pages for teachers. They don’t give the answer; the students are supposed to find out on their own. Unfortunately, I can’t find the results of any elementary school seed-counting projects, either. Anyone out there have a watermelon in the fridge? Keep an eye on the number of seeds when you eat it, will ya?
Of course you don’t have to eat a whole watermelon(has anyone ever done this? - I always seem to end up throwing the last quarter in the compost heap); you could just count the seeds in a slice and extrapolate.
Mangetout that won’t take into account any variance in seed density based on the location from which the slice is taken!
Oz needs to take a variety of slices, count the seeds in each different type of slice, then take the weighted average of the seed density based on the relative proportion of the type of slice to the whole. Only then can we have an accurate estimate of the actual number of seeds in a watermelon. This doesn’t even take into account any differences in watermelon variety or seed maturity!!! head explodes
Or he could just eat a half watermelon, 2.5lbs should be easy enough and will take into account any changes in seed density.
Even then, half the melon will only contain half the seeds if they are symmetrically distributed; as a crude example, an apple has a core with five-fold radial symmetry; it would be possible to cut it in half in such a way as to have the seeds from two of the chambers in one half and three in the other.
If the watermelon seeds were distributed in, say, three narrow zones with 120[sup]o[/sup] separation, it would be possible to have quite a sizeable discrepancy between the numbers of seeds unless you happened to cut the pattern in half symmetrically.
A transverse section of a sample fruit and examination of the pattern of seed inclusion should determine whether this is likely to be an issue; my guess is that (if the seeds are not simply evenly distributed) there will be five(or multiples thereof)fol symmetry, as this is present in the flowers of Cucurbitacae.
An alternative to these sampling ideas would be to get a hold of some other people and eat the whole thing
Before I’d start anything I’d find out where Ozzie19 found a 5lb watermelon. It would be about the size of a cantaloupe.
Or just pull some number out of your ass; there are so many variables involved (size and variety of fruit, degree of pollination).
Exactly 624.
What? You doubt me? Go ahead and prove me wrong, I dare ya!
See - the trick is to answer quickly and authoritatively.
Oh and the group counting thing might not work because some people eat the seeds (they aren’t all that bad actually).
Exactly? Exactly!? I only got 623. What’s going on?
You must have swallowed one. 
You swallowed one without chewing?
Oh my.
Now a watermelon plant will grow inside your brain and millions of tiny spiders will crawl out of the wound (or something like that).
Go to a store that sells watermelons. Buy one that looks of ‘average size’. There. What, is the melon next to it going to have 100x the seeds? Plus, if other bored dopers were to post the results of their seed-counting exercises, we could get an even better idea.
There is a way way around this, as well. Example:
“Hey, guys, try not to eat the seeds. Or at least, try to count them. I’d like to know for the good of humanity.”
There, see how easy that was?
Of course, the numeral/rectum method might be equally effective.
When you eat a watermelon, along with the hard black seeds, you’ll often find a large number of soft flat white seeds; I think I’m right in saying that these would have been hard and black too if the flower that preceeded the fruit had received more pollen grains, if this is true (botanists?) then there could well be a very significant difference between the number of black seeds in fruits (we should call them berries actually) of similar size. Not likely to be different by a factor of 100 though, no.
I’d just like to say I love you people!
the range is 234-408, avg. around 300.