Baby oil or glycerin for snow globe?
Glycerin has a density of about 1.2gm per cm3, while baby oil has density of 0.8.

The less dense baby oil offers less resistance and I imagine will give quicker falling flakes of snow. How much difference you actually notice is the real test. I’d be trying both.

There may be no difference at all. If that’s the case then go with the cheaper liquid.

PDF hart listing glycerol densities at various dilutions. 100% glycerol is the first entry

I can’t see an authoritative figure for baby oil but the answer is given by several online contributors who offer the same number.