Seed float test

I've always been told that if seeds are viable they will sink, if not they will float. For most things this seems to be accurate, probably due to the fact that a dead seed will have more air and less water inside.

I have a bunch of leftover (?!) fruit seeds this spring, so I decided to test it.

Apricots:

17 floated, 14 sank (in the shell):
3 floated when in the shells and when I cracked them
---One sprouted on 4/4
14 floated when in the shells but sank when I cracked them
---One sprouted on 4/2
---One sprouted on 4/20
8 sank both times
---One sprouted on 4/2
---One sprouted on 4/3
6 sank when in the shells but floated when I cracked them

No visible difference. I separated the seeds into those groups.

After soaking 24 hours I filled the bottles with sphegnum moss to soak up the water and create the ideal microclimate for the seedlings. All of the seeds appear to be healthy. One of the sank/sank batch split within 24 hours.

They've been in the refrigerator all winter so I think the "cold stratification" criteria has been met.

As if 4/28, all the remaining seeds are still firm but no more have sprouted. Based on this test I don't see any difference in sprouting rates between the seeds that floated and the seeds that sank. The others could probably sprout eventually, but this test is over.