name for a light fluffy powder

I’ve worked with powders that are so light and fluffy they are hard to handle. You open the container and the powder just puffs out. I know there is a scientific term for this (floculate?)

What is it?

The scientific term for tiny particles suspended in air is aerosol.

An aerosol is suspended, as scr4 says. If something is a powder, that is, if it is particles sitting together at the bottom of a container, it’s not an aerosol.
There are powders that take the form of dendrites of primary particles that are agglomerated into much larger, but open and lacy, branching chains. Silica can do this, for example as the soot from a silane (SiH4) flame, and it is called fumed silica, and is very light and fluffy. One brand is Cabosil. Carbon soot can also take this form. I don’t know of a name for these collectively, though.

Hmm. Usually, materials with that consistency are micronized (processed to a particle size measurable in microns; say, a maximum size of 10 or 100 microns). In a manufacturing or lab environment, we’d say that it “flies” or “dusts.”

When I used to lyophilize (basically freeze dry) biological mixtures like, say crude E. coli cultures or pureed cow brains, the resulting powders (the lyophilizates) often had these properties. They tended to be a bit hygroscopic too, which caused swelling when exposed to air.